udf: remove redundant variable netype

The variable netype is assigned a value that is never read, the assignment
is redundant the variable can be removed.

Message-Id: <20230105134925.45599-1-colin.i.king@gmail.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>