msm: mpm: move header to include/irqchip

MPM hardware acts as an interrupt controller when the apps has gone
to deep sleep states where GIC (the apps main interrupt controller)
has power collapsed. The MPM monitors certain GIC and GPIO lines
while APPS is sleeping and wakesup the apps when a favourable
transition is seen on those monitored lines.

It is an interrupt controller hence move its header to include/irqchip.

Change-Id: I2599784dd91bba73b51ca197e8da69b9c56f78a5
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>