imx: kontron-sl-mx8mm: Add support for Kontron Electronics SoM SL i.MX8MM OSM-S

This adds support for the Kontron Electronics SoM SL i.MX8MM OSM-S
and the matching baseboard BL i.MX8MM OSM-S.

The SoM hardware complies to the Open Standard Module (OSM) 1.0
specification, size S (https://sget.org/standards/osm).

The existing board configuration for the non-OSM SoM is reused and
allows to detect the SoM variant at runtime.

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 3b80ed2..749b25a 100644
--- a/configs/kontron-sl-mx8mm_defconfig
+++ b/configs/kontron-sl-mx8mm_defconfig
@@ -73,6 +73,7 @@
 CONFIG_CMD_EXT4_WRITE=y
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y
+CONFIG_OF_LIST="imx8mm-kontron-bl imx8mm-kontron-bl-osm-s"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
@@ -120,6 +121,7 @@
 CONFIG_DM_REGULATOR=y
 CONFIG_DM_REGULATOR_PCA9450=y
 CONFIG_DM_RTC=y
+CONFIG_RTC_RV3028=y
 CONFIG_RTC_RV8803=y
 CONFIG_DM_SERIAL=y
 CONFIG_MXC_UART=y