radeonsi/gfx9: fix VM fault with fetched instance divisors
We need to account for SGPR locations in merged shaders. This case is exercised by KHR-GL45.enhanced_layouts.vertex_attrib_locations Fixes: 79c2e738 ("radeonsi/gfx9: use SPI_SHADER_USER_DATA_COMMON") Reviewed-by:Marek Olšák <marek.olsak@amd.com> (cherry picked from commit df5ebe0c)