Patch for device tree binding in ti-linux-4.4.y branch of
the ti-linux-kernel-dev repo which renames the labels of
the USR LED nodes from usrN to the trigger name
Normal labels:
* beaglebone:green:usr0
* beaglebone:green:usr1
* beaglebone:green:usr2
* beaglebone:green:usr3
Alternate labels:
* beaglebone:green:heartbeat
* beaglebone:green:mmc0
* beaglebone:green:cpu0
* beaglebone:green:mmc1
Related issue:
Doesn't support Ubuntu core beaglebone leds #129https://github.com/adafruit/adafruit-beaglebone-io-python/issues/129
