Add feature to opt-in the Badger2040W wiring that uses GPIO 22 for the LED

To see the blinking led on a Badger 2040W, run:

$ cargo run --release --features wifi --example badger_blinky

Author: naufraghi

boards/pimoroni_badger2040/Cargo.toml

@@ -46,3 +46,6 @@ disable-intrinsics = ["rp2040-hal/disable-intrinsics"]
 
 # This enables ROM functions for f64 math that were not present in the earliest RP2040s
 rom-v2-intrinsics = ["rp2040-hal/rom-v2-intrinsics"]
+
+# Define a feature to toggle between Badger2040 and Badger2040W
+wifi = []

boards/pimoroni_badger2040/src/lib.rs

@@ -81,11 +81,13 @@ hal::bsp_pins!(
     },
     Gpio20 { name: inky_dc },
     Gpio21 { name: inky_res },
+    /// GPIO 22 is connected to activity LED of the badger2040W.
+    #[cfg(feature = "wifi")] Gpio22 { name: led },
     Gpio23 { name: user_sw },
     /// GPIO 24 is connected to vbus_detect of the badger2040.
     Gpio24 { name: vbus_detect },
     /// GPIO 25 is connected to activity LED of the badger2040.
-    Gpio25 { name: led },
+    #[cfg(not(feature = "wifi"))] Gpio25 { name: led },
     Gpio26 { name: inky_busy },
     Gpio27 { name: vref_power },
     Gpio28 { name: vref_1v24 },