arm64: dts: qcom: Add base X1E80100 dtsi and the QCP dts

Add base dtsi and QCP board (Qualcomm Compute Platform) dts file for
X1E80100 SoC, describing the CPUs, GCC and RPMHCC clock controllers,
geni UART, interrupt controller, TLMM, reserved memory, interconnects,
SMMU and LLCC nodes.

Co-developed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Rajendra Nayak <quic_rjendra@quicinc.com>
Co-developed-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>