Add STM32U5 example.

examples/stm32u5/.cargo/config.toml

@@ -0,0 +1,18 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace STM32F429ZITx with your chip as listed in `probe-run --list-chips`
+runner = "probe-run --chip STM32U585AIIx"
+
+rustflags = [
+  # LLD (shipped with the Rust toolchain) is used as the default linker
+  "-C", "link-arg=--nmagic",
+  "-C", "link-arg=-Tlink.x",
+  "-C", "link-arg=-Tdefmt.x",
+
+  # Code-size optimizations.
+  "-Z", "trap-unreachable=no",
+  "-C", "inline-threshold=5",
+  "-C", "no-vectorize-loops",
+]
+
+[build]
+target = "thumbv7em-none-eabi"