Modify屏幕BacklightDriver

Modify the copied driver file

Here is an example of the aw9364 backlight driver：

Initialize

In the aw9364_init function, initialize the control pin LCD_BACKLIGHT_CONTROL_PIN as a GPIO output and set it to low (turn off the backlight)。

Set backlight brightness

In the callback function backligt_set, convert the brightness percentage passed down from the upper layer（Based on the brightness level supported by the backlight IC），Then pass it to the sif_aw9364_set_backlight function to set the brightness。

Read backlight brightness

In the callback function backligt_get, use the variable aw9364_bl to return the brightness because this backlight chip does not support reading the brightness level。