spirv: Add support for DerivativeGroup capabilities

As defined in SPV_NV_compute_shader_derivatives. These control how the
invocations are arranged in a CS when doing derivative and related
operations (which are also enabled by the extension).

Since we expect valid SPIR-V, we don't need to do more work at SPIR-V
level to enable the derivative and related operations to be called.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/shader_info.h

@@ -35,6 +35,7 @@ extern "C" {
 struct spirv_supported_capabilities {
    bool address;
    bool atomic_storage;
+   bool derivative_group;
    bool descriptor_array_dynamic_indexing;
    bool device_group;
    bool draw_parameters;