Change MSAA sample-count error to warning

Change MSAA sample-count error to warning on high resolution render
targets. The lack of samples is likely not detected by a person and
the real samples are not exposed to the application under GLES 3.0.

Bug: 25685990
Change-Id: Ib95447caeb8b1110fda6299222041c38a61d6112
1 file changed