Implement RDNA2 per-invocation scratch memory

src/graphics/shader/recompiler/ShaderRecompiler.h

@@ -18,6 +18,7 @@ struct CompileOptions {
 	uint32_t                    wave_size       = 64;
 	uint32_t                    user_data_base  = 0;
 	uint32_t                    user_data_count = 64;
+	uint32_t                    scratch_dwords  = 0;
 	uint64_t                    shader_hash     = 0;
 	uint64_t                    shader_base     = 0;
 	std::optional<uint64_t>     flat_memory_base;