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/T1042D4RDB_SDCARD_defconfig b/configs/T1042D4RDB_SDCARD_defconfig
index 92037c5..b64f295 100644
--- a/configs/T1042D4RDB_SDCARD_defconfig
+++ b/configs/T1042D4RDB_SDCARD_defconfig
@@ -21,6 +21,8 @@
 CONFIG_SYS_FSL_PBL_PBI="$(SRCTREE)/board/freescale/t104xrdb/t104x_pbi.cfg"
 CONFIG_SYS_FSL_PBL_RCW="$(SRCTREE)/board/freescale/t104xrdb/t1042d4_sd_rcw.cfg"
 CONFIG_BOOTDELAY=10
+CONFIG_USE_BOOTCOMMAND=y
+CONFIG_BOOTCOMMAND="setenv bootargs root=/dev/ram rw console=$consoledev,$baudrate $othbootargs;setenv ramdiskaddr 0x02000000;setenv fdtaddr 0x00c00000;setenv loadaddr 0x1000000;bootm $loadaddr $ramdiskaddr $fdtaddr"
 CONFIG_SILENT_CONSOLE=y
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_BOARD_EARLY_INIT_F=y