[media] gspca - pac7302: Cleanup source

- copyright change
- use the kbuild module name for messages
- change module author
- remove '__' from the variable types
- use u8 instead of 'unsigned char'
- simplify the error messages
- remove useless initialization
- remove useless traces

Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>