Currently iomap_file_buffered_write_punch_delalloc can be called from
XFS either with the invalidate lock held or not.  To fix this while
keeping the locking in the file system and not the iomap library
code we'll need to life the locking up into the file system.

To prepare for that, open code iomap_file_buffered_write_punch_delalloc
in the only caller, and instead export iomap_write_delalloc_release.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>