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/T2080RDB_SPIFLASH_defconfig b/configs/T2080RDB_SPIFLASH_defconfig
index ea43361..579a36b 100644
--- a/configs/T2080RDB_SPIFLASH_defconfig
+++ b/configs/T2080RDB_SPIFLASH_defconfig
@@ -25,6 +25,8 @@
 CONFIG_SYS_FSL_PBL_PBI="board/freescale/t208xrdb/t2080_pbi.cfg"
 CONFIG_SYS_FSL_PBL_RCW="board/freescale/t208xrdb/t2080_spi_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_BOARD_EARLY_INIT_R=y
 # CONFIG_SPL_FRAMEWORK is not set
 CONFIG_SPL_SPI_BOOT=y