drm/bridge: panel: Set pre_enable_prev_first from drmm_panel_bridge_add

Commit 5ea6b170 ("drm/panel: Add prepare_prev_first flag to drm_panel")
added code to copy prepare_prev_first from drm_panel to pre_enable_prev_first
in drm_bridge when called through devm_panel_bridge_add, but
missed drmm_panel_bridge_add.

Add the same code to drmm_panel_bridge_add.

Fixes: 5ea6b170

 ("drm/panel: Add prepare_prev_first flag to drm_panel")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20221222185213.3773336-1-dave.stevenson@raspberrypi.com