stm32mp: dram_init: Get RAM size from DT if no RAM driver found

In case there is no RAM driver retrieve RAM size from DT as fallback.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
index 7f37b0d..a1e77a4 100644
--- a/arch/arm/mach-stm32mp/dram_init.c
+++ b/arch/arm/mach-stm32mp/dram_init.c
@@ -24,8 +24,11 @@
 	int ret;
 
 	ret = uclass_get_device(UCLASS_RAM, 0, &dev);
-	if (ret) {
-		log_debug("RAM init failed: %d\n", ret);
+	/* in case there is no RAM driver, retrieve DDR size from DT */
+	if (ret == -ENODEV) {
+		return fdtdec_setup_mem_size_base();
+	} else if (ret) {
+		log_err("RAM init failed: %d\n", ret);
 		return ret;
 	}
 	ret = ram_get_info(dev, &ram);