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/ls1012afrdm_qspi_defconfig b/configs/ls1012afrdm_qspi_defconfig
index b40c632..d4ca5e7 100644
--- a/configs/ls1012afrdm_qspi_defconfig
+++ b/configs/ls1012afrdm_qspi_defconfig
@@ -21,6 +21,7 @@
 CONFIG_BOOTDELAY=10
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS0,115200 root=/dev/ram0 earlycon=uart8250,mmio,0x21c0500 quiet lpj=250000"
+CONFIG_BOOTCOMMAND="run distro_bootcmd;run qspi_bootcmd"
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_CMD_GREPENV=y