drm/msm/dpu: remove hard-coded linewidth limit for writeback

Remove the hard-coded limit for writeback and lets start using
the one from catalog instead.

changes in v3:
	- correct the Fixes tag

Fixes: d7d0e73f

 ("drm/msm/dpu: introduce the dpu_encoder_phys_* for writeback")
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/489888/
Link: https://lore.kernel.org/r/1655406084-17407-3-git-send-email-quic_abhinavk@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>