udf: Rename udf_warning to udf_warn

Rename udf_warning to udf_warn for consistency with normal logging
uses of pr_warn.

Rename function udf_warning to _udf_warn.
Remove __func__ from uses and move __func__ to a new udf_warn
macro that calls _udf_warn.
Add \n's to uses of udf_warn, remove \n from _udf_warn.
Coalesce formats.

Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>