soc: qcom: Add snapshot for QSEE IPC IRQ driver

This snapshot is taken as of msm-4.14 'commit <f63747b8> ("Merge
"UPSTREAM commit 'eec33478' 09/30"")'.

This introduces a basic driver for cascading interrupts from QSEE. This
driver will perform the common interrupt handling code for interrupts
from QSEE incluiding clearing the interrupt through a register write.

Change-Id: Ib6484ad0bc1c2f123c381e0683e880e422ed6bb0
Signed-off-by: Chris Lew <clew@codeaurora.org>