fs/buffer.c: remove block_write_full_page_endio()

The last in-tree caller of block_write_full_page_endio() was removed in
January 2013.  It's time to remove the EXPORT_SYMBOL, which leaves
block_write_full_page() as the only caller of
block_write_full_page_endio(), so inline block_write_full_page_endio()
into block_write_full_page().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dheeraj Reddy <dheeraj.reddy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index c18d95b..1a64e7a 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -429,7 +429,7 @@
 		block_start = bh_offset(bh);
 		if (block_start >= len) {
 			/*
-			 * Comments copied from block_write_full_page_endio:
+			 * Comments copied from block_write_full_page:
 			 *
 			 * The page straddles i_size.  It must be zeroed out on
 			 * each and every writepage invocation because it may