Less code and more efficient.

Got ride of a variable that counted the number of devices in
cx8802_unregister_driver() but was never used.  Looked leftover from a
cut&paste.
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Reviewed-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>