Convert CONFIG_CMD_ASKENV et al to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_ASKENV
   CONFIG_CMD_BMP
   CONFIG_CMD_BOOTD
   CONFIG_CMD_CACHE
   CONFIG_CMD_CRC32
   CONFIG_CMD_DHCP
   CONFIG_CMD_ENV
   CONFIG_CMD_EXPORTENV
   CONFIG_CMD_EXT2
   CONFIG_CMD_EXT4
   CONFIG_CMD_FLASH
   CONFIG_CMD_FS_GENERIC
   CONFIG_CMD_FUSE
   CONFIG_CMD_GPIO
   CONFIG_CMD_GPT
   CONFIG_CMD_GREPENV
   CONFIG_CMD_I2C
   CONFIG_CMD_IMLS
   CONFIG_CMD_IMPORTENV
   CONFIG_CMD_LOADB
   CONFIG_CMD_LOADS
   CONFIG_CMD_MEMINFO
   CONFIG_CMD_MII
   CONFIG_CMD_MTDPARTS
   CONFIG_CMD_NAND
   CONFIG_CMD_NAND_TRIMFFS
   CONFIG_CMD_NFS
   CONFIG_CMD_PCA953X
   CONFIG_CMD_PCA953X_INFO
   CONFIG_CMD_PCI
   CONFIG_CMD_PING
   CONFIG_CMD_READ
   CONFIG_CMD_SF
   CONFIG_CMD_SPI
   CONFIG_CMD_SPL
   CONFIG_CMD_SPL_WRITE_SIZE
   CONFIG_CMD_TIME
   CONFIG_CMD_TRACE
   CONFIG_CMD_UBI
   CONFIG_CMD_UBIFS
   CONFIG_CMD_UNZIP
   CONFIG_FS_EXT4

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/am335x_shc_netboot_defconfig b/configs/am335x_shc_netboot_defconfig
index 91c1ce7..f03f1fa 100644
--- a/configs/am335x_shc_netboot_defconfig
+++ b/configs/am335x_shc_netboot_defconfig
@@ -42,6 +42,7 @@
 CONFIG_CMD_MMC=y
 # CONFIG_CMD_PINMUX is not set
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_CACHE=y
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="am335x-shc"
 CONFIG_ENV_IS_IN_MMC=y