drm/amdgpu: add fw release for sdma v5_0

sdma fw isn't released when module exit
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Wenhui Sheng <Wenhui.Sheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c

@@ -1299,8 +1299,12 @@ static int sdma_v5_0_sw_fini(void *handle)
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 	int i;
 
-	for (i = 0; i < adev->sdma.num_instances; i++)
+	for (i = 0; i < adev->sdma.num_instances; i++) {
+		if (adev->sdma.instance[i].fw != NULL)
+			release_firmware(adev->sdma.instance[i].fw);
+
 		amdgpu_ring_fini(&adev->sdma.instance[i].ring);
+	}
 
 	return 0;
 }