Directly use AON GPIO trigger instead of IPM.
In the past, SW did not allow arc to receive AON GPIO interrupt.
So, interrupt from BMI160 was routed to x86 cpu. Then, x86 cpu
passed the event to arc through IPM. But, SW was updated and arc
is able to directly receive interrupt from AON GPIO now. So, IPM
is not needed any more. Let's remove IPM related code and use
GPIO as the default trigger source.
This change is on top of the bmi160 sample app change to not use
IPM.
Change-Id: I49d8040764d03b24e09d89e66643c020ef63a3c9
Signed-off-by: Baohong Liu <baohong.liu@intel.com>