FROMGIT: drm_bridge: register content protect property

Some bridges can update HDCP status based on userspace requests if they
support HDCP.

The HDCP property is created after connector initialization and before
registration, just like other connector properties.

Add the content protection property to the connector if a bridge
supports HDCP.

Change-Id: Ic4f9c9ad243a3ccdc9fe074b935df7430674edb1
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Fei Shao <fshao@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250812082135.3351172-2-fshao@chromium.org
Bug: 438243152
(cherry picked from commit 407a2fab
     https://gitlab.freedesktop.org/drm/misc/kernel.git

 drm-misc-next)
Signed-off-by: Hubert Mazur <hmazur@google.com>