drm/bridge/tc358775: Fix for dual-link LVDS

Fixed wrong register shift for single/dual link LVDS output.

Tested-by: Jiri Vanek <jirivanek1@gmail.com>
Signed-off-by: Jiri Vanek <jirivanek1@gmail.com>
Reviewed-by: Vinay Simha BN <simhavcs@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220106190027.1498-1-jirivanek1@gmail.com