drm/amdgpu: add Arcturus chip_name for init sdma microcode

So we load the proper firmware for arcturus.
Signed-off-by: Le Ma <le.ma@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c

@@ -369,6 +369,9 @@ static int sdma_v4_0_init_microcode(struct amdgpu_device *adev)
 		else
 			chip_name = "raven";
 		break;
+	case CHIP_ARCTURUS:
+		chip_name = "arcturus";
+		break;
 	default:
 		BUG();
 	}