soc: qcom: Add bgcom driver for sdm429w

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
GPIOs present between SDM429W and BG.

Change-Id: I7122824da2814b37a82f4a480068a5677970db7d
Signed-off-by: Chandrasekhar Mattaparthy <cmatta@codeaurora.org>