configs: SECURE_BOOT: Enable CONFIG_CMD_EXT4_WRITE

As part of chain of trust with confidentiality along with distro
boot, linux kernel image needs to be stored in encrypted form on
ext4 boot partition. So enable CONFIG_CMD_EXT4_WRITE in case of
Secure boot on ARM based platforms.

Signed-off-by: Sumit Garg <sumit.garg@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: York Sun <york.sun@nxp.com>

board/freescale/common/Kconfig

@@ -7,6 +7,8 @@ config CHAIN_OF_TRUST
 	select SHA_HW_ACCEL
 	select SHA_PROG_HW_ACCEL
 	select ENV_IS_NOWHERE
+	select CMD_EXT4 if ARM
+	select CMD_EXT4_WRITE if ARM
 	bool
 	default y