Bug register/value inversions in USB exchanges.
Exposure and gain controls added for rev 12a.
Separate the functions and controls of the revisions 12a and 72a.
Signed-off-by: NJean-Francois Moine <moinejf@free.fr>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>