msm:cpp: Fix for spurious interrupts from CPP hardware

When power up the CPP, it generates spurious interrupts
that can confuse microntroller and halt it. This fix
clears the interrupt requests from CPP before enable
Microcontroller at "Open Camera" event.

Change-Id: I3b75f2513efc30fb0f35dd086464f0b6c3a6ff9b
Signed-off-by: Iliya Varadzhakov <ivarad@codeaurora.org>