Fix examples broken by the macro fix.

examples/stm32f7/src/bin/eth.rs

@@ -106,7 +106,7 @@ async fn main(spawner: Spawner) -> ! {
             let r = socket.write_all(&buf).await;
             if let Err(e) = r {
                 info!("write error: {:?}", e);
-                return;
+                continue;
             }
             Timer::after(Duration::from_secs(1)).await;
         }

examples/stm32f7/src/bin/sdmmc.rs

@@ -10,7 +10,7 @@ use embassy_stm32::{interrupt, Config};
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::main]
-async fn main(_spawner: Spawner) -> ! {
+async fn main(_spawner: Spawner) {
     let mut config = Config::default();
     config.rcc.sys_ck = Some(mhz(200));
     config.rcc.pll48 = true;
@@ -41,6 +41,4 @@ async fn main(_spawner: Spawner) -> ! {
     let card = unwrap!(sdmmc.card());
 
     info!("Card: {:#?}", Debug2Format(card));
-
-    loop {}
 }