Convert CONFIG_USE_BOOTCOMMAND et al to Kconfig

This converts the following to Kconfig:
   CONFIG_USE_BOOTCOMMAND
   CONFIG_BOOTCOMMAND
   CONFIG_RAMBOOTCOMMAND
   CONFIG_NFSBOOTCOMMAND

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ids8313_defconfig b/configs/ids8313_defconfig
index cf4e8c0..f21811f 100644
--- a/configs/ids8313_defconfig
+++ b/configs/ids8313_defconfig
@@ -128,6 +128,8 @@
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="Enter password - autoboot in %d seconds...\n"
 CONFIG_AUTOBOOT_DELAY_STR="ids"
+CONFIG_USE_BOOTCOMMAND=y
+CONFIG_BOOTCOMMAND="run boot_cramfs"
 CONFIG_USE_PREBOOT=y
 CONFIG_PREBOOT="echo;echo Type \"run nfsboot\" to mount root filesystem over NFS;echo"
 # CONFIG_DISPLAY_BOARDINFO is not set