fix up sdk version

Neutree · Neutree · commit b10b99a10bff · 2019-04-02T09:24:26.000+08:00
diff --git a/cores/arduino/kendryte-standalone-sdk b/cores/arduino/kendryte-standalone-sdk
@@ -1 +1 @@
-Subproject commit ee61b9eefdee2a9c36cab0856c0323a0b966ebbc
+Subproject commit 9fb218233809f174689561322d04643d97efa08c
