Improve install-to-RAM verification for ISO boots

audit/internal/platform/install_to_ram_other.go

@@ -7,3 +7,7 @@ import "errors"
 func loopChangeFD(loopDev, newFile string) error {
 	return errors.New("LOOP_CHANGE_FD not available on this platform")
 }
+
+func bindMount(src, dst string) error {
+	return errors.New("bind mount not available on this platform")
+}