drm/msm/dpu: fix maxlinewidth for writeback block

drm/msm/dpu: fix maxlinewidth for writeback block

Writeback block for sm8250 was using the default maxlinewidth
of 2048. But this is not right as it supports upto 4096.

This should have no effect on most resolutions as we are
still limiting upto maxlinewidth of SSPP for adding the modes.

Fix the maxlinewidth for writeback block on sm8250.

changes in v3:
	- correct the Fixes tag

Fixes: 54688e5a6789 ("drm/msm/dpu: add writeback blocks to the sm8250 DPU catalog")
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/489887/
Link: https://lore.kernel.org/r/1655406084-17407-2-git-send-email-quic_abhinavk@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>