arm: mach-k3: j721s2_init: Enable memory with CONFIG_K3_J721E_DDRSS

Make that condition more generic by checking if the memory controller
driver is enabled instead of using the EVM's config.

Signed-off-by: Dominik Haller <d.haller@phytec.de>
diff --git a/arch/arm/mach-k3/j721s2_init.c b/arch/arm/mach-k3/j721s2_init.c
index 712a7e2..a5be84b 100644
--- a/arch/arm/mach-k3/j721s2_init.c
+++ b/arch/arm/mach-k3/j721s2_init.c
@@ -219,7 +219,7 @@
 	struct udevice *dev;
 	int ret;
 
-	if (IS_ENABLED(CONFIG_TARGET_J721S2_R5_EVM)) {
+	if (IS_ENABLED(CONFIG_K3_J721E_DDRSS)) {
 		ret = uclass_get_device_by_name(UCLASS_MISC, "msmc", &dev);
 		if (ret)
 			panic("Probe of msmc failed: %d\n", ret);