V4L/DVB (5562): Radio-gemtek-pci.c Replace gemtek_pci_ioctl to use video_ioctl2

Convert radio-gemtek-pci to use video_ioctl2

Signed-off-by: Douglas Schilling Landgraf <dougsland@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>