Bluetooth: add support for controlling regulators for hastings

Dymanically controlling of these regulators is to save power
consumption of hastings. That is to say, these regulators shall
be turned off when they are not used.

Change-Id: I47e5c2686e5abd7c489edb36da4e2ef5a0429fb5
Signed-off-by: Yanfei Zhou <zyanfei@codeaurora.org>