mailbox: apcs-ipc: Add support for sdxprairie

The qcom-apcs-ipc-mailbox driver maps the shared apps
register to trigger interrupts to remote subsystems. This
change adds the correct configuration for sdxprairie.

Change-Id: Ie31a97cc62ff12c2e628975ad8f0df493a49f6de
Signed-off-by: Chris Lew <clew@codeaurora.org>