fs/writeback: remove unnecessary return in writeback_inodes_sb

writeback_inodes_sb doesn't have return value, just remove unnecessary
return in it.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Link: https://lore.kernel.org/r/20240228091958.288260-7-shikemeng@huaweicloud.comReviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/fs-writeback.c

@@ -2735,7 +2735,7 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr);
  */
 void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
 {
-	return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
+	writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
 }
 EXPORT_SYMBOL(writeback_inodes_sb);