Use an updated golang.org/x/crypto with various assembly related fixes

diff --git a/src/golang.org/x/crypto b/src/golang.org/x/crypto
index 8a549a1948fc5271eb24f36dcb0d3b47dec75a16..41d678d1df78cd0410143162dff954e6dc09300f 160000 (submodule)
--- a/src/golang.org/x/crypto
+++ b/src/golang.org/x/crypto
@@ -1 +1 @@
-Subproject commit 8a549a1948fc5271eb24f36dcb0d3b47dec75a16
+Subproject commit 41d678d1df78cd0410143162dff954e6dc09300f