drm/msm/dpu: simplify dpu_encoder_phys_wb_init()

drm/msm/dpu: simplify dpu_encoder_phys_wb_init()

There is no need to assign a result to temp varable just to return it
after a goto. Drop the temporary variable and goto and return the result
directly.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Abhinav Kumar <quic_abhinavk@quicinc.com> # sc7280
Patchwork: https://patchwork.freedesktop.org/patch/540639/
Link: https://lore.kernel.org/r/20230601172236.564445-8-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>