filesystems: add set_nlink()

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/affs/amigaffs.c b/fs/affs/amigaffs.c
index 8f12723..de37ec8 100644
--- a/fs/affs/amigaffs.c
+++ b/fs/affs/amigaffs.c
@@ -215,7 +215,7 @@
 				break;
 			default:
 				if (!AFFS_TAIL(sb, bh)->link_chain)
-					inode->i_nlink = 1;
+					set_nlink(inode, 1);
 			}
 			affs_free_block(sb, link_ino);
 			goto done;