V4L/DVB: gspca_xirlink_cit: New gspca subdriver replacing v4l1 usbvideo/ibmcam.c

The old usbvideo ibmcam driver needs to be replaced with a v4l2 driver
preferably using the gspca webcam framework rather then the old usbvideo
framework.

This new gspca sub driver sets a first step in that direction. The ibmcam
driver supports 4 different model webcams. This new driver (for now) only
supports Model 3 cameras, as my test cam is a Model 3 cam, or so I thought.

Upon reading:
http://www.linux-usb.org/ibmcam/


I learned that the IBM Netcamera Pro I have even though having the same
usb id and the same bcd version is different from the Model 3 cameras
supported by the ibmcam driver. So this new gscpa subdriver supports Model 3
cameras (untested), and the IBM Netcamera Pro. Currently use with the
IBM Netcamera Pro requires a module parameter. I hope to be able to
autodetect which is which in the future.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>