drm/msm/dsi: use the correct VREG_CTRL_1 value for 4nm cphy

Use the same value as the downstream driver. This change is needed for CPHY
mode to work correctly.

Fixes: 8b034e67

 ("drm/msm/dsi: add support for DSI-PHY on SM8550")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/566987/
Link: https://lore.kernel.org/r/20231110000216.29979-1-jonathan@marek.ca
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>