config.conf: Add ppc64 kvmsmall config (bsc#1137361).
    
    - Remove superfluous i2c drivers from ppc64 config
      -CONFIG_I2C_ALGOPCA=m
      -CONFIG_I2C_AMD8111=m
      -CONFIG_I2C_CBUS_GPIO=m
      -CONFIG_I2C_DESIGNWARE_CORE=y
      -CONFIG_I2C_DESIGNWARE_PLATFORM=y
      -CONFIG_I2C_DESIGNWARE_PCI=m
      -CONFIG_I2C_OCORES=m
      -CONFIG_I2C_PCA_PLATFORM=m
    
    Can't get rid of i2c in kvmsmall anyway but at least the DW i2c is gone.