rk平台调试：failed to find backlight: -517

 
 pwm-backlight backlight: failed to apply initial PWM state: -22
 pwm-backlight: probe of backlight failed with error -22
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517
 panel-simple-dsi fde20000.dsi.0: failed to find backlight: -517

以上log是由于pwm对应的gpio被复用导致。