graphics: Update RAW16 format comments

RAW16 format could be used together with depth dataspace.
The buffer contents in this case will be phase detection
statistics data.

Bug: 36015382
Test: testPDStats
Change-Id: Ied1c179193abef62a87fcec6f0906528ed58ea2b
(cherry picked from commit 23699d63143fd9d47f8584c6627e5c38838b333f)
1 file changed