arm: Add support for Qualcomm Snapdragon family

First supported chip is APQ8016 (that is compatible with MSM8916).
Drivers in SoC code:
- Reset controller (PSHOLD)
- Clock controller (very simple clock configuration for MMC and UART)

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>