The function "drm_of_find_panel_or_bridge" has been deprecated in
favor of "devm_drm_of_get_bridge".

Switch to the new function and reduce boilerplate.
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220228182904.22982-1-jose.exposito89@gmail.com