drm/amdgpu: Remove the unneeded result variable 'r'

Return the value sdma_v4_0_start() directly instead of storing it in
another redundant variable.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -2002,7 +2002,6 @@ static int sdma_v4_0_sw_fini(void *handle)
 
 static int sdma_v4_0_hw_init(void *handle)
 {
-	int r;
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 
 	if (adev->flags & AMD_IS_APU)
@@ -2011,9 +2010,7 @@ static int sdma_v4_0_hw_init(void *handle)
 	if (!amdgpu_sriov_vf(adev))
 		sdma_v4_0_init_golden_registers(adev);
 
-	r = sdma_v4_0_start(adev);
-
-	return r;
+	return sdma_v4_0_start(adev);
 }
 
 static int sdma_v4_0_hw_fini(void *handle)