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/arch/arm/mach-kirkwood/Kconfig b/arch/arm/mach-kirkwood/Kconfig
index ddfae8c..8aa5428 100644
--- a/arch/arm/mach-kirkwood/Kconfig
+++ b/arch/arm/mach-kirkwood/Kconfig
@@ -34,6 +34,7 @@
 config TARGET_KM_KIRKWOOD
 	bool "KM_KIRKWOOD Board"
 	select BOARD_LATE_INIT
+	imply CMD_CRAMFS
 
 config TARGET_NET2BIG_V2
 	bool "LaCie 2Big Network v2 NAS Board"