cli: add basic probe-rs support

OpenOCD can be somewhat outdated. `probe-rs` is a more modern tool
written in Rust with many interesting features, like built-in RTT
logging support.

This commit just adds basic support, to be able to flash devices with
probe-rs and debug them.

compileopts/config.go

@@ -539,7 +539,7 @@ func (c *Config) Programmer() (method, openocdInterface string) {
 	case "openocd", "msd", "command", "adb":
 		// The -programmer flag only specifies the flash method.
 		return c.Options.Programmer, c.Target.OpenOCDInterface
-	case "bmp":
+	case "bmp", "probe-rs":
 		// The -programmer flag only specifies the flash method.
 		return c.Options.Programmer, ""
 	default:

compileopts/target.go

@@ -67,6 +67,7 @@ type TargetSpec struct {
 	ADBPreCommands   []string `json:"adb-pre-commands,omitempty"`
 	ADBPushRemote    string   `json:"adb-push-remote,omitempty"`
 	ADBPostCommands  []string `json:"adb-post-commands,omitempty"`
+	ProbeRSChip      string   `json:"probe-rs-chip,omitempty"`
 	CodeModel        string   `json:"code-model,omitempty"`
 	RelocationModel  string   `json:"relocation-model,omitempty"`
 	WITPackage       string   `json:"wit-package,omitempty"`