ARM: dts: stm32: Reinstate SPL_SYS_MMCSD_RAW_MODE on DH STM32MP15xx DHSOM

Commit 2a00d73d081a ("spl: mmc: Try to clean up raw-mode options")
broke booting from SD card on STM32MP15xx , reinstate raw mode SD
boot configuration options and select the correct raw mode partition
for STM32MP15xx to fix SD boot on STM32MP15xx DHSOM.

Fixes: 2a00d73d081a ("spl: mmc: Try to clean up raw-mode options")
Reported-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/configs/stm32mp15_dhsom.config b/configs/stm32mp15_dhsom.config
index efc1495..04ee9bf 100644
--- a/configs/stm32mp15_dhsom.config
+++ b/configs/stm32mp15_dhsom.config
@@ -57,11 +57,14 @@
 CONFIG_SPL_STACK=0x30000000
 CONFIG_SPL_SYS_MALLOC=y
 CONFIG_SPL_SYS_MALLOC_SIZE=0x1d00000
+CONFIG_SPL_SYS_MMCSD_RAW_MODE=y
 CONFIG_SPL_TEXT_BASE=0x2FFC2500
 CONFIG_SPL_USB_GADGET=y
 CONFIG_STM32_ADC=y
 CONFIG_SYSRESET_SYSCON=y
 CONFIG_SYS_BOOTCOUNT_ADDR=0x5C00A14C
+CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=0x3
+CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_PARTITION=y
 CONFIG_SYS_MALLOC_F_LEN=0x3000
 CONFIG_SYS_PBSIZE=1050
 CONFIG_PREBOOT="run dh_preboot"