msm: camera: isp: Add convert RAW10 to RAW8 support in CSID

For some sensors input stream can be of format MIPI_RAW_10 but
the output of CSID should be 8 bit.
This adds support to preserve the 8 MSB and truncate 2 LSBs.

CRs-Fixed: 2940817
Change-Id: I097593bac27ee4ae8859a682c0564f8fdd8c7e91
Signed-off-by: Gaurav Jindal <gjindal@codeaurora.org>