imx: kontron-sl-mx8mm: Add support for loading from SPI NOR in SPL

This was initially enabled, but got accidentally dropped while
migrating Kconfig options and resyncing the defconfig in:

commit 9802154a94d6 ("configs: Resync with savedefconfig")

Let's enable this again to be able to boot from SPI NOR.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/configs/kontron-sl-mx8mm_defconfig b/configs/kontron-sl-mx8mm_defconfig
index f6ebfaf..ff306cd 100644
--- a/configs/kontron-sl-mx8mm_defconfig
+++ b/configs/kontron-sl-mx8mm_defconfig
@@ -19,6 +19,8 @@
 CONFIG_SPL_DRIVERS_MISC=y
 CONFIG_BOOTCOUNT_BOOTLIMIT=3
 CONFIG_SPL=y
+CONFIG_SPL_SPI_FLASH_SUPPORT=y
+CONFIG_SPL_SPI=y
 CONFIG_SYS_LOAD_ADDR=0x42000000
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT=y
@@ -42,6 +44,8 @@
 CONFIG_SPL_I2C=y
 CONFIG_SPL_DM_SPI_FLASH=y
 CONFIG_SPL_POWER=y
+CONFIG_SPL_SPI_LOAD=y
+CONFIG_SYS_SPI_U_BOOT_OFFS=0x58000
 CONFIG_SPL_WATCHDOG=y
 CONFIG_SPL_ATF=y
 CONFIG_SYS_CBSIZE=256