kill wait_on_page_writeback_range

All callers really want the more logical filemap_fdatawait_range interface,
so convert them to use it and merge wait_on_page_writeback_range into
filemap_fdatawait_range.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/jbd2/commit.c

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index d4cfd6d..c5edc13 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -286,7 +286,7 @@
 		if (err) {
 			/*
 			 * Because AS_EIO is cleared by
-			 * wait_on_page_writeback_range(), set it again so
+			 * filemap_fdatawait_range(), set it again so
 			 * that user process can get -EIO from fsync().
 			 */
 			set_bit(AS_EIO,