SoC: qcom: add support for SDM845

Hi-end qualcomm chip, introduced in late 2017.
Mostly used in flagship phones and tablets of 2018.
Features:
- arm64 arch
- total of 8 Kryo 385 Gold / Silver cores
- Hexagon 685 DSP
- Adreno 630 GPU

Tested only as second-stage bootloader.

Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Stephan Gerhold <stephan@gerhold.net>