arm64: dts: Add msm8998 SoC and MTP board support

Add initial device tree support for the Qualcomm MSM8998 SoC and
MTP8998 evaluation board.

Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Signed-off-by: Imran Khan <kimran@codeaurora.org>
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
[bjorn: Restructured, removed its node and moved to SPDX headers]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>