Update to the latest ASF4 which includes an I2C timeout extension while waiting for clock stretching.

tannewt · tannewt · commit 73dadb0669fb · 2018-06-11T18:37:48.000-07:00
Fixes #778
diff --git a/ports/atmel-samd/asf4 b/ports/atmel-samd/asf4
@@ -1 +1 @@
-Subproject commit 02e264253c76b85c567ecdfce69ad0de0970da63
+Subproject commit cdde379f78989436590a556cadbc0e201666ee04
