Avoid clobbering of YUV layout for flexible formats

Bug: 21787806

In function DeriveYUVLayout in fw/rs/driver/rsdAllocation.cpp, skip
initialization of DrvState if the yuv format is the flexible YCbCr
format.

Change-Id: Ie2c5253b2ed048887d034ad8793d0558f2cd7d4f
(cherry picked from commit 31c406a5991858d68886d35b6e9bf03acc0b3288)
1 file changed