drm/bridge: adv7511: Initialize regulators

Maintain a table of regulator names expect by ADV7511 and ADV7533.
Use regulator_bulk_* api to configure these.

Initialize and enable the regulators during probe itself. Controlling
these dynamically is left for later.

Cc: dri-devel@lists.freedesktop.org
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>