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/ls2081ardb_defconfig b/configs/ls2081ardb_defconfig
index fb12277..2fcb9c8 100644
--- a/configs/ls2081ardb_defconfig
+++ b/configs/ls2081ardb_defconfig
@@ -20,7 +20,7 @@
 CONFIG_BOOTDELAY=10
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS1,115200 root=/dev/ram0 earlycon=uart8250,mmio,0x21c0600 ramdisk_size=0x2000000 default_hugepagesz=2m hugepagesz=2m hugepages=256"
-# CONFIG_USE_BOOTCOMMAND is not set
+CONFIG_BOOTCOMMAND="sf probe 0:0; sf read 0x806c0000 0x6c0000 0x40000; env exists mcinitcmd && env exists secureboot && esbc_validate 0x806C0000; sf read 0x80d00000 0xd00000 0x100000; env exists mcinitcmd && fsl_mc lazyapply dpl 0x80d00000; run distro_bootcmd;run qspi_bootcmd; env exists secureboot && esbc_halt;"
 CONFIG_MISC_INIT_R=y
 CONFIG_CMD_GREPENV=y
 CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS=5