zink: verify geometry shader feature
We shouldn't try to use geometry shaders on implementations that don't support them. So let's verify the feature before using it.
Fixes: 8028991f ("zink: enable gs pipe caps")
We shouldn't try to use geometry shaders on implementations that don't support them. So let's verify the feature before using it.
Fixes: 8028991f ("zink: enable gs pipe caps")