JFS: fix sparse warnings by moving extern declarations to headers

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 41bf078..aa1cc7b 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -726,12 +726,12 @@
 	page_cache_release(page);
 }
 
-extern void hold_metapage(struct metapage *mp)
+void hold_metapage(struct metapage *mp)
 {
 	lock_page(mp->page);
 }
 
-extern void put_metapage(struct metapage *mp)
+void put_metapage(struct metapage *mp)
 {
 	if (mp->count || mp->nohomeok) {
 		/* Someone else will release this */