udf: Convert all file types to use udf_write_end()

Switching address_space_operations while a file is used is difficult to
do in a race-free way. To be able to use single address_space_operations
in UDF, create udf_write_end() function that is able to handle both
normal and in-ICB files.

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