udf: Merge linux specific translation into CS0 conversion function

Current implementation of udf_translate_to_linux function does not
support multi-bytes characters at all: it counts bytes while calculating
extension length, when inserting CRC inside the name it doesn't
take into account inter-character boundaries and can break into
the middle of the character.

The most efficient way to properly support multi-bytes characters is
merging of translation operations directly into conversion function.
This can help to avoid extra passes along the string or parsing
the multi-bytes character back into unicode to find out it's length.

Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Jan Kara <jack@suse.cz>