Update to 4.2-rc1.
    
    - Xen needs updating.
    - ARM configs need updating.
    - DWARF2 / stack unwinding need updating.
    - 5 patches eliminated.
    - Config changes:
      - Generic:
        - RCU_EXPERT=n (default)
        - SCHED_OMIT_FRAME_POINTER=y (temporary)
        - ACPI_REV_OVERRIDE_POSSIBLE=y (default)
        - OF_UNITTEST=n (default)
        - THERMAL_WRITABLE_TRIPS=n
        - THERMAL_DEFAULT_GOV_STEP_WISE=y
        - THERMAL_GOV_POWER_ALLOCATOR=n
        - SND_PROC_FS=y
        - DEFERRED_STRUCT_PAGE_INIT=y
        - PROC_CHILDREN=y
        - RCU_EQS_DEBUG=n
    
      - Networking:
        - GENEVE_CORE=m
        - TCP_CONG_CDG=m
        - NETFILTER_INGRESS=y
        - NF_TABLES_NETDEV=m
        - NET_CLS_FLOWER=m
        - SUNRPC_XPRT_RDMA=m
    
      - Network drivers:
        - BE2NET_HWMON=y (option to existing driver)
        - EZCHIP_NPS_MANAGEMENT_ENET=m
        - MLX5_CORE_EN=y (option to existing driver)
        - SFC_MCDI_LOGGING=y (option to existing driver)
        - DP83867_PHY=m
        - MT7601U=m
        - IEEE802154_ATUSB=n
        - PHY_PXA_28NM_HSIC=n
        - PHY_PXA_28NM_USB2=n
        - PHY_TUSB1210=n
        - DELL_RBTN=m
    
      - Input:
        - INPUT_LEDS=y
        - LEDS_AAT1290=n
        - LEDS_BCM6328=n
        - LEDS_BCM6358=n
        - LEDS_TLC591XX=n
        - LEDS_KTD2692=n
        - TOUCHSCREEN_WDT87XX_I2C=m
        - INPUT_DRV2665_HAPTICS=m
        - SERIAL_SC16IS7XX_I2C=y
        - SERIAL_SC16IS7XX_SPI=n
    
      - Chargers:
        - CHARGER_BQ24257=m
        - CHARGER_BQ25890=m
        - CHARGER_RT9455=m
    
      - Sensors:
        - SENSORS_TC74=m
        - MAX63XX_WATCHDOG=n
    
      - GPU:
        - DRM_AMDGPU=m
        - DRM_AMDGPU_CIK=n (experimental)
        - DRM_AMDGPU_USERPTR=y
        - DRM_VIRTIO_GPU=m
        - USB_ULPI_BUS=m
    
      - Android:
        - STAGING_BOARD=n
    
      - Accelerometers:
        - STK8312=m
        - STK8BA50=m
    
      - Light sensors:
        - ACPI_ALS=m
        - BH1750=n
        - STK3310=n
        - MMC35240=n
        - BMC150_MAGN=n
    
      - Non-Transparent Bridging:
        - NTB_PINGPONG=n
        - NTB_TOOL=n
        - NTB_TRANSPORT=m
        - NTB=n (ppc)
    
      - Other:
        - F2FS_FS_ENCRYPTION=y
    
      - Crypto:
        - CRYPTO_RSA=m
        - CRYPTO_CHACHA20POLY1305=m
        - CRYPTO_ECHAINIV=m
        - CRYPTO_POLY1305=m
        - CRYPTO_CHACHA20=m
        - CRYPTO_842=m
        - CRYPTO_JITTERENTROPY=m
        - CRYPTO_USER_API_AEAD=m
    
      - NV-DIMM:
        - ACPI_NFIT=m
        - ACPI_NFIT_DEBUG=n
        - ND_BLK=m
        - BTT=y
    
      - Bluetooth:
        - BT_HCIBTUSB_RTL=y (default)
    
      - NFC:
        - NFC_NCI_UART=m
        - NFC_MRVL_UART=m
        - NFC_ST_NCI=m
        -  NFC_ST_NCI_I2C=m
    
      - Storage:
        - SCSI_SNIC=m
        -  SCSI_SNIC_DEBUG_FS=n
        - DM_CACHE_SMQ=m (EXPERIMENTAL)
        - MMC_MTK=m
    
      - x86:
        - X86_DEBUG_FPU=n
        - PUNIT_ATOM_DEBUG=n
        - UNISYS_VISORBUS=m
        - UNISYS_VISORNIC=m
        - NTB_INTEL=m
        - SCIF_BUS=m
        - SCIF=m
        - INTEL_QUARK_DTS_THERMAL=m
        - INTEL_PMC_IPC=m
    
      - ppc:
        - GIANFAR=n
        - SERIAL_8250_INGENIC=n
    
      - ppc64:
        - OPAL_PRD=m
        - MTD_POWERNV_FLASH=m
        - CRYPTO_DEV_NX_COMPRESS_PSERIES=m
        - CRYPTO_DEV_NX_COMPRESS_POWERNV=m
        - CRYPTO_DEV_NX_COMPRESS_CRYPTO=m
    
      - Cross-endian virtio:
        - TUN_VNET_CROSS_LE=n
        - VHOST_CROSS_ENDIAN_LEGACY=n
    
      - ARM:
        - SPI_ZYNQMP_GQSPI=n
        - AHCI_CEVA=n (Xilinx Zynq UltraScale+ MPSoC.)
        - QCOM_SPMI_TEMP_ALARM=n
        - THUNDER_NIC_PF=n
        - THUNDER_NIC_VF=n
        - THUNDER_NIC_BGX=n
        - LIQUIDIO=n
        - COMMON_CLK_CDCE925=n
        - UIO_PRUSS=n