fs: Convert CONFIG_CMD_CRAMFS to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_CRAMFS

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: imply CMD_CRAMFS for keymile]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/UCP1020_SPIFLASH_defconfig b/configs/UCP1020_SPIFLASH_defconfig
index 77ae65c..4e5e0c1 100644
--- a/configs/UCP1020_SPIFLASH_defconfig
+++ b/configs/UCP1020_SPIFLASH_defconfig
@@ -20,6 +20,7 @@
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
+CONFIG_CMD_CRAMFS=y
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
 CONFIG_MTD_NOR_FLASH=y