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/ls2088ardb_qspi_SECURE_BOOT_defconfig b/configs/ls2088ardb_qspi_SECURE_BOOT_defconfig
index 3c436ab..cfa300f 100644
--- a/configs/ls2088ardb_qspi_SECURE_BOOT_defconfig
+++ b/configs/ls2088ardb_qspi_SECURE_BOOT_defconfig
@@ -18,7 +18,7 @@
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_QSPI_BOOT=y
 CONFIG_BOOTDELAY=10
-# 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