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/smdkc100_defconfig b/configs/smdkc100_defconfig
index 8e0b999..4746985 100644
--- a/configs/smdkc100_defconfig
+++ b/configs/smdkc100_defconfig
@@ -12,6 +12,8 @@
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="root=/dev/mtdblock5 ubi.mtd=4 rootfstype=cramfs console=ttySAC0,115200n8 mem=128M  mtdparts=s3c-onenand:256k(bootloader),128k@0x40000(params),3m@0x60000(kernel),16m@0x360000(test),-(UBI)"
+CONFIG_USE_BOOTCOMMAND=y
+CONFIG_BOOTCOMMAND="run ubifsboot"
 CONFIG_HUSH_PARSER=y
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_SYS_PROMPT="SMDKC100 # "