intel/sandybridge: initialize variable

Otherwise cache_base may be uninitialized.

Change-Id: Ie91f9567cea24114723a5362f52052d6ec22a6b8
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/10724
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/northbridge/intel/sandybridge/mrccache.c

@@ -72,7 +72,8 @@ static u32 get_mrc_cache_region(struct mrc_data_container **mrc_region_ptr)
 		if (fmap_locate_area_as_rdev("RW_MRC_CACHE", &rdev) == 0) {
 			region_size = region_device_sz(&rdev);
 			*mrc_region_ptr = rdev_mmap_full(&rdev);
-		}
+		} else
+			*mrc_region_ptr = NULL;
 	} else {
 		*mrc_region_ptr = cbfs_boot_map_with_leak("mrc.cache",
 							CBFS_TYPE_MRC_CACHE,