[media] dvb-usb-gp8psk: get firmware and fpga versions

This patch adds retrieval of firmware and FPGA versions of Genpix devices.
That information is useful for users who experience performance differences
with the various firmware versions, and may want to use a specific firmware
that best suits their needs.

Example dmesg output:
gp8psk: FW Version = 2.09.4 (0x20904)  Build 2009/04/02
gp8psk: FPGA Version = 1

Signed-off-by: Derek Kelly <user.vdr@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>