radv: disassemble SPIR-V binaries with RADV_DEBUG=spirv

This introduces a new separate option because the output can
be quite verbose. If spirv-dis is not found in the path, this
debug option is useless.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/vulkan/radv_pipeline.c

@@ -207,6 +207,9 @@ radv_shader_compile_to_nir(struct radv_device *device,
 		uint32_t *spirv = (uint32_t *) module->data;
 		assert(module->size % 4 == 0);
 
+		if (device->debug_flags & RADV_DEBUG_DUMP_SPIRV)
+			radv_print_spirv(module, stderr);
+
 		uint32_t num_spec_entries = 0;
 		struct nir_spirv_specialization *spec_entries = NULL;
 		if (spec_info && spec_info->mapEntryCount > 0) {