drm/msm/dsi: fix hdisplay calculation for CMD mode panel

drm/msm/dsi: fix hdisplay calculation for CMD mode panel

Commit ac47870fd795 ("drm/msm/dsi: fix hdisplay calculation when
programming dsi registers") incorrecly broke hdisplay calculation for
CMD mode by specifying incorrect number of bytes per transfer, fix it.

Fixes: ac47870fd795 ("drm/msm/dsi: fix hdisplay calculation when programming dsi registers")
Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/709917/
Link: https://lore.kernel.org/r/20260307111250.105772-2-mitltlatltl@gmail.com
[DB: fixed commit message]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>