vidc: Map userspace allocated buffers into video smmu.

Buffers allocated in userspace are registered with
video driver for video core to use them. Video driver
uses the msm mapped buffer API's to get the device
address for those buffers. This address is then passed
on to video core.

Change-Id: I33dae3c90feb6c320cf0d422adf17b14eee03625
Signed-off-by: Deepak Kotur <dkotur@codeaurora.org>