V4L/DVB (6551): tda8290: rule out tda988x before detecting tda8290/tda8295

To ensure prevention of detecting a tda9885/6/7 as a tda8290 or tda8295, we
will rule out the tda988x before testing the tda8290 / tda8295 id registers.

We read 8 bytes from the chip.  If they are all equal, then it is not a
tda829x, or some other error has occurred.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>