msm: camera: MSM FD face detection driver

MSM FD (Face detection) driver - Detects faces from a given input buffer.

The driver implements standard V4L2 interface, and supports
V4L2 event interface. Uses standard V4L2 IOCTLs and controls.
However there is one private IOCTL used to
obtain the result of the driver:

"VIDIOC_MSM_FD_GET_RESULT"

Compat support is also added for this IOCTL.

The driver can operate simultaneously
with multiple open file descriptors.

Change-Id: I50ebdd9c966c18dec27a06630a0cbd0affc0b1bb
Signed-off-by: Gjorgji Rosikopulos <grosik@codeaurora.org>