nb/intel: Use "if (!ptr)" in preference to "if (ptr == NULL)"

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Change-Id: I6d0d945011fa046b974c6f4554cb9fb15e523afb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67578
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/sandybridge/raminit_mrc.c b/src/northbridge/intel/sandybridge/raminit_mrc.c
index c276d4c..a308d07 100644
--- a/src/northbridge/intel/sandybridge/raminit_mrc.c
+++ b/src/northbridge/intel/sandybridge/raminit_mrc.c
@@ -111,7 +111,7 @@
 	pei_data->mrc_input = mrc_cache_current_mmap_leak(MRC_TRAINING_DATA,
 							  MRC_CACHE_VERSION,
 							  &mrc_size);
-	if (pei_data->mrc_input == NULL) {
+	if (!pei_data->mrc_input) {
 		/* Error message printed in find_current_mrc_cache */
 		return;
 	}