zephyr: device: gpio: Add Send to Gpio and GpioPin

Thread safety is managed by using a token on the operations, so these
become Send safe.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

zephyr/src/device/gpio.rs

@@ -42,6 +42,9 @@ pub struct Gpio {
     pub(crate) device: *const raw::device,
 }
 
+// SAFETY: Gpio's can be shared with other threads.  Safety is maintained by the Token.
+unsafe impl Send for Gpio {}
+
 impl Gpio {
     /// Constructor, used by the devicetree generated code.
     ///
@@ -73,6 +76,9 @@ pub struct GpioPin {
     pub(crate) pin: raw::gpio_dt_spec,
 }
 
+// SAFETY: GpioPin's can be shared with other threads.  Safety is maintained by the Token.
+unsafe impl Send for GpioPin {}
+
 impl GpioPin {
     /// Constructor, used by the devicetree generated code.
     #[allow(dead_code)]