Add utility function for 16-bit texture formats.

Bug 20891368

Change-Id: I6fb0ed00b903fe86c3b5c730842d28e9c212e04e
Reviewed-on: https://swiftshader-review.googlesource.com/3100
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
2 files changed