how can i get /lib/firmware/am335x-pm-firmware.bin in beaglebone black 4.4.91-ti-r133

Actually i am trying to interface IR receiver with beaglebone black, based on this website. i tried to change kernel to 3.8.13 but i cant so i trying to install lirc-BBB patch in 4.4.91-ti-r133 kernel only and i stucked in copying files cp /lib/firmware/am335x-pm-firmware.bin ./firmware/ .
am335x -pm-firmare.bin missing in firmware folder, so can anyone helps me to get solved

thank you