nir/xfb: do not use bare interface type
In commit 3b3653c4 we decided not to use bare types; hence do not use bare type when comparing with interface type to find out if the xfb variable is an array block.
This fixes dEQP-VK.transform_feedback.* tests.
Fixes: 3b3653c4 ("nir/spirv: don't use bare types, remove assert in split vars for testing") CC: Dave Airlie airlied@redhat.com CC: Jason Ekstrand jason@jlekstrand.net