Update to 4.15-rc1.
    
    - Eliminated 74 patches.
    - ARM configs need updating.
    - Config changes:
      - General:
        - CPU_ISOLATION=y
        - GUP_BENCHMARK=n
      - x86:
        - X86_INTEL_UMIP=y
        - PINCTRL_CEDARFORK=m
        - INTEL_SOC_PMIC_CHTDC_TI=m
        - INTEL_WMI_THUNDERBOLT=m
        - DELL_SMBIOS_WMI=m
        - DELL_SMBIOS_SMM=m
        - CHT_DC_TI_PMIC_OPREGION=y
        - RPMSG_CHAR=m
      - i386:
        - IR_SPI=m
        - IR_GPIO_CIR=m
        - IR_GPIO_TX=m
        - IR_PWM_TX=m
      - powerpc:
        - PPC_RADIX_MMU_DEFAULT=y (default)
        - MEM_SOFT_DIRTY=n (needs arch expert review)
        - PINCTRL=n
        - PPC_FAST_ENDIAN_SWITCH=n (default)
      - s390:
        - GCC_PLUGINS=n
        - MEM_SOFT_DIRTY=(needs arch expert review)
        - PINCTRL=n
        - FORTIFY_SOURCE=y
      - s390/zfcpdump:
        - BPF_STREAM_PARSER=n
        - MTD=n
      - Network:
        - NET_SCH_CBS=m
        - VSOCKETS_DIAG=m
        - DP83822_PHY=m
        - RENESAS_PHY=m
        - THUNDERBOLT_NET=m
      - Input:
        - TOUCHSCREEN_EXC3000=m
        - TOUCHSCREEN_HIDEEP=m
        - TOUCHSCREEN_S6SY761=m
        - DRM_I2C_ADV7511_CEC=y
      - Misc:
        - IPMI_PROC_INTERFACE=y
        - GPIO_MAX3191X=m
        - MANAGER_SBS=m
        - W1_SLAVE_DS28E17=m
        - SENSORS_MAX6621=m
        - SENSORS_MAX31785=m
        - CEC_GPIO=m
        - TYPEC_TPS6598X=m
        - RPMSG_VIRTIO=m
        - IIO_CROS_EC_ACCEL_LEGACY=m
        - RFD77402=m
        - NTB_SWITCHTEC=m
        - MMC_SDHCI_OMAP=m
      - Filesystems:
        - XFS_ONLINE_SCRUB=n (still experimental)
        - BTRFS_FS_REF_VERIFY=n
        - CRAMFS_BLOCKDEV=y
        - CRAMFS_MTD=y
        - INTEGRITY_TRUSTED_KEYRING=y
      - Crypto:
        - CRYPTO_SM3=m
        - SIGNED_PE_FILE_VERIFICATION=y
        - SYSTEM_TRUSTED_KEYS (empty)
        - SYSTEM_EXTRA_CERTIFICATE=n
        - SECONDARY_TRUSTED_KEYRING=n
      - LEDS:
        - LEDS_APU=m
        - LEDS_TRIGGER_ACTIVITY=m
      - RTC:
        - RTC_DRV_PCF85363=m
      - Xen:
        - XEN_PVCALLS_FRONTEND=n
      - Graphics:
        - DRM_AMD_DC=y
        - DRM_AMD_DC_PRE_VEGA=y
        - DRM_AMD_DC_FBC=y ?
        - DRM_AMD_DC_DCN1_0=y
        - DEBUG_KERNEL_DC=n
        - NOUVEAU_DEBUG_MMU=n
      - Storage:
        - NVME_MULTIPATH=y
      - IB:
        - MLX4_CORE_GEN2=y
      - Sound:
        - SND_SOC_INTEL_SST_TOPLEVEL=m
        - SND_SOC_INTEL_BAYTRAIL=m
      - Testing:
        - KCOV_ENABLE_COMPARISONS=y (syzkaller)
        - BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK=n
        - PREEMPTIRQ_EVENTS=y
        - TEST_FIND_BIT=n
        - PKCS7_TEST_KEY=n
        - CHASH_SELFTEST=n
        - CHASH_STATS=n