soc: qcom: Add Blackghost(BG) chip PIL driver

BG is a companion chip for msm8909 for low power needs.
Add BG PIL driver to provide load, subsystem restart
and ramdump collection support.

The driver loads the BG firmware into memory and sends
a command to the secure userspace application to initiate
secure transfer of the BG firmware into internal memory
of BG and reset BG. The subsystem restart depends on four
GPIOs present between MSM8909 and BG.

Change-Id: I6e5db44879acb74d39961103715db7417e1bef39
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>