iomap: remove the iomap_file_buffered_write_punch_delalloc return value

iomap: remove the iomap_file_buffered_write_punch_delalloc return value

iomap_file_buffered_write_punch_delalloc can only return errors if either
the ->punch callback returned an error, or if someone changed the API of
mapping_seek_hole_data to return a negative error code that is not
-ENXIO.

As the only instance of ->punch never returns an error, an such an error
would be fatal anyway remove the entire error propagation and don't
return an error code from iomap_file_buffered_write_punch_delalloc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240910043949.3481298-6-hch@lst.de
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>