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/k2g_hs_evm_defconfig b/configs/k2g_hs_evm_defconfig
index 2c20ee3..a5ebb42 100644
--- a/configs/k2g_hs_evm_defconfig
+++ b/configs/k2g_hs_evm_defconfig
@@ -15,7 +15,7 @@
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT_IMAGE_POST_PROCESS=y
 CONFIG_OF_BOARD_SETUP=y
-# CONFIG_USE_BOOTCOMMAND is not set
+CONFIG_BOOTCOMMAND="run findfdt; run envboot; run run_mon_hs; run init_${boot}; run get_fit_${boot}; bootm ${addr_fit}#${name_fdt}"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SYS_I2C_EEPROM_ADDR_LEN=2