V4L/DVB (6068): cx88-alsa: Use pci_dev->revision

The revision is part of the pci_dev struct, so there is no need to read it in.

Stop storing the revision and latency in the chip struct, since they're never
used after being printed out when the driver loads.

linux/pci.h wasn't included.  It was getting picked up something else,
probably cx88.h, but this file uses struct pci_dev so it should include pci.h.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>