mm/page_alloc: improve memmap_pages dbg msg

Make debug message more accurate.

Link: https://lkml.kernel.org/r/20210531091908.1738465-6-aisheng.dong@nxp.com
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Dong Aisheng

mm/page_alloc.c

@@ -7383,7 +7383,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat)
 					pr_debug("  %s zone: %lu pages used for memmap\n",
 						 zone_names[j], memmap_pages);
 			} else
-				pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
+				pr_warn("  %s zone: %lu memmap pages exceeds freesize %lu\n",
 					zone_names[j], memmap_pages, freesize);
 		}