msm_11ad: support voltage GPIO connected to 11ad card

On some platforms there is a GPIO used for DC to 11ad card.
This GPIO behaves exactly like the existing wigig-en.

Change-Id: Id015dce253f134bd39d4bfa3780941fd007e35fa
Signed-off-by: Alexei Avshalom Lazar <ailizaro@codeaurora.org>