feat(msm8916): initial platform port

Introduce the bare mimimum base of the msm8916 BL31 port. This is
pretty much just a standard platform "skeleton" with CPU/memory
initialization and an UART driver. This allows booting into
e.g. U-Boot with working UART output.

Note that the plat/qti/msm8916 port is completely separate and does not
make use of anything in plat/qti/common at the moment. The main reason
for that is that plat/qti/common is heavily focused around having a
binary "qtiseclib" component, while the MSM8916 port is fully
open-source (and therefore somewhat limited to publicly documented

In the future it might be possible to re-use some of the open-source
parts in plat/qti/common (e.g. spmi_arb.c or pm_ps_hold.c) but it's
not strictly required for the basic functionality supported so far.

Change-Id: I7b4375df0f947b3bd1e55b0b52b21edb6e6d175b
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
10 files changed