drm/amdgpu: Use ternary operator in `vcn_v1_0_start()`

Remove the boilerplate of declaring a variable and using an if else
statement by using the ternary operator.
Reviewed-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c

@@ -1102,13 +1102,8 @@ static int vcn_v1_0_start_dpg_mode(struct amdgpu_device *adev)
 
 static int vcn_v1_0_start(struct amdgpu_device *adev)
 {
-	int r;
-
-	if (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG)
-		r = vcn_v1_0_start_dpg_mode(adev);
-	else
-		r = vcn_v1_0_start_spg_mode(adev);
-	return r;
+	return (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG) ?
+		vcn_v1_0_start_dpg_mode(adev) : vcn_v1_0_start_spg_mode(adev);
 }
 
 /**