Implement R5G6B5 clear.

Bug 20891368

Change-Id: I5c283589c1fb08003194e668c66ade4d0fe36842
Reviewed-on: https://swiftshader-review.googlesource.com/3250
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
2 files changed