drivers/mrc_cache: Avoid `sizeof` on struct type

Where applicable, use the size of the associated variable.

Change-Id: Icf4f1c8fe9f54c44b041a65eb46d6ec9f9fd6367
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55902
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
diff --git a/src/drivers/mrc_cache/mrc_cache.c b/src/drivers/mrc_cache/mrc_cache.c
index f97031d..841c97e 100644
--- a/src/drivers/mrc_cache/mrc_cache.c
+++ b/src/drivers/mrc_cache/mrc_cache.c
@@ -486,7 +486,7 @@
 
 	struct update_region_file_entry entries[] = {
 		[0] = {
-			.size = sizeof(struct mrc_metadata),
+			.size = sizeof(*new_md),
 			.data = new_md,
 		},
 		[1] = {
@@ -696,7 +696,7 @@
 		.data_checksum = compute_ip_checksum(data, size),
 	};
 	md.header_checksum =
-		compute_ip_checksum(&md, sizeof(struct mrc_metadata));
+		compute_ip_checksum(&md, sizeof(md));
 
 	if (CONFIG(MRC_STASH_TO_CBMEM)) {
 		/* Store data in cbmem for use in ramstage */