drivers: wireless: Add option to change WiFi power mode on suspend

When this config is enabled, "wifi_pm" module parameter
is utilized to change power mode of WiFi on suspend
and save more power.

[hammerhead: Makefile is re-structured to compile this config]

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Fixes for GCC 4.8
sensors_adsp: fix to gcc 4.8