2.2 TFT SPI LCD pwm polarity change

Hello there,
I am using this dts with an Adafruit 2.2 TFT SPI LCD screen: https://pastebin.com/vrUZ0Wde
To drive backlit, pwm is used. My problem is that it is not inverted and BeagleBone Black pins cant give/ sink to much current, not enough for backlit. So in order to drive not inverted pwm i have to use 2 FETS (N driving P) instead of one P one:

BL - BeagleBone Black pin for backlit
BL_P - LCD backlit pin

If I could invert the pwm signal in the dts, then i could use BSS84P directly, without BSS123.
I Would aprichiate all help in this matter!