handle empty hciconfig response to avoid panic

Author: BuildTools

Diff for: hw/linux/hciconfig/hciconfig.go

@@ -1,6 +1,7 @@
 package hciconfig
 
 import (
+	"errors"
 	"strings"
 
 	"github.com/muka/go-bluetooth/hw/linux/cmd"
@@ -14,6 +15,10 @@ func GetAdapters() ([]HCIConfigResult, error) {
 		return nil, err
 	}
 
+	if len(out) == 0 {
+		return nil, errors.New("hciconfig provided no response")
+	}
+
 	list := []HCIConfigResult{}
 	parts := strings.Split(out, "\nhci")