fs: Kconfig: Add a separate option for FS_CRAMFS

Rather than using CMD_CRAMFS for both the filesystem and its command, we
should have a separate option for each. This allows us to enable CRAMFS
support without the command, if desired, which reduces U-Boot's size
slightly.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: imply FS_CRAMFS for keymile]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 4145fcf..5451398 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -901,6 +901,7 @@
 
 config CMD_CRAMFS
 	bool "Enable the 'cramfs' command"
+	depends on FS_CRAMFS
 	help
 	  This provides commands for dealing with CRAMFS (Compressed ROM
 	  filesystem). CRAMFS is useful when space is tight since files are