fw-rust: Move PWM handling into screen module

Move the handling of the PWM signal which generates the dimmable
backlight signal into the screen module.

firmware/rust/src/main.rs

@@ -58,9 +58,6 @@ impl ClockGenerator {
         let dp = Peripherals::take().unwrap();
         let pins = pins!(dp);
 
-        // Set display PWM backlight pin as output
-        pins.pd5.into_output();
-
         // Init SPI
         let (spi, _) = Spi::new(
             dp.SPI,
@@ -79,7 +76,13 @@ impl ClockGenerator {
         );
 
         Self {
-            screen: Screen::new(dp.TC0, spi, pins.pb0.into_output(), pins.pb1.into_output()),
+            screen: Screen::new(
+                dp.TC0,
+                spi,
+                pins.pd5.into_output(),
+                pins.pb0.into_output(),
+                pins.pb1.into_output(),
+            ),
             tc1: dp.TC1,
             exint: dp.EXINT,
             delay: Delay::<MHz8>::new(),