spirv: Use the same types for resource indices as pointers

We need more space than just a 32-bit scalar and we have to burn all
that space anyway so we may as well expose it to the driver.  This also
fixes a subtle bug when UBOs and SSBOs have different pointer types.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/intel/compiler/brw_vec4_nir.cpp

@@ -467,6 +467,7 @@ vec4_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
    }
 
    case nir_intrinsic_get_buffer_size: {
+      assert(nir_src_num_components(instr->src[0]) == 1);
       unsigned ssbo_index = nir_src_is_const(instr->src[0]) ?
                             nir_src_as_uint(instr->src[0]) : 0;