main: rewrite display creation code to use type aliases and fewer cfg branches

src/platform/smart_leds_lib.rs

@@ -123,6 +123,7 @@ pub mod spi {
     use crate::render::{Display, Surface};
     use crate::task::Task;
     use crate::platform::smart_leds_lib::SmartLedDisplay;
+    use crate::DisplayInit;
 
     use esp_idf_svc::hal::{
         prelude::*,