ENGR00209062-2: mx6dq and mx6dl dual camera support

ENGR00209062-2: mx6dq and mx6dl dual camera support

dual camera support for mx6q and mx6dl:
1. let mipi and parallel camera working on different csi
2. the two camera can work independently and synchronously
3. the two camera will be registered and different video
   device(/dev/video0, /dev/video1)
4. when both camera are working, the can not use the same
   ipu channel, that is, when camera one using PRP_ENC_MEM
   or PRP_VF_MEM channel, the other one can only use CSI_MEM

   this is the driver part.

Signed-off-by: Wu Guoxing <b39297@freescale.com>