examples: move atcmd into lorawan

Signed-off-by: deadprogram <ron@hybridgroup.com>

examples/lora/lorawan/atcmd/radio.go

@@ -0,0 +1,10 @@
+package main
+
+import (
+	"errors"
+)
+
+var (
+	errRadioNotFound = errors.New("radio not found")
+	errRxTimeout     = errors.New("radio RX timeout")
+)