delete systemcmds/mixer

src/drivers/pca9685_pwm_out/main.cpp

@@ -530,8 +530,6 @@ IIC communication is based on CDev::I2C
 It is typically started with:
 $ pca9685_pwm_out start -a 64 -b 1
 
-Use the `mixer` command to load mixer files.
-`mixer load /dev/pwm_outputX etc/mixers/quad_x.main.mix`
 The number X can be acquired by executing
 `pca9685_pwm_out status` when this driver is running.
 )DESCR_STR");