svga: if we get nr_samples==1, store nr_samples=0

We need to be more careful not to treat nr_samples=1 as an msaa surface.
This patch prevents us from errantly declaring an MSAA shader resource
with 1 sample.

No Piglit regressions, fixes the above-described errors.

Reviewed-by: Neha Bhende <bhenden@vmware.com>
1 file changed