rebalance_interrupts: one shot IRQ rebalancer

rebalance_interrupts is a one shot IRQ rebalancer.
It scans /sys/kernel/irq for related IRQ actions
that haven't any affinity to a core.  It then assigns
them evenly to the policy0 group cores.

Bug: 148403062
Test: ran "rebalance_interrupts" as root after boot, saw
no additional IRQs rebalanced.  Verified via /proc/interrupts
that interrupts had been distributed.

Change-Id: I76745d4620024a1f21ecf70d11e0c14d2eb85cef
3 files changed