Add the missing sanity check on the bridge counter to avoid corrupting
data beyond the fixed-sized bridge array in case there are ever more
than eight bridges.
Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
Cc: stable@xxxxxxxxxxxxxxx # 5.17
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>