Get struct timeval from sys/time.h.

The naclports patch switches sys/types.h to sys/time.h. Per
http://pubs.opengroup.org/onlinepubs/009604499/basedefs/sys/time.h.html
this is correct.

Change-Id: If6d56cb28fa16a1d8b4515a45532434f6c23a29d
Reviewed-on: https://boringssl-review.googlesource.com/6624
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/internal.h b/ssl/internal.h
index dde605b..61038b7 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -155,7 +155,7 @@
 #include <winsock2.h>
 #pragma warning(pop)
 #else
-#include <sys/types.h>
+#include <sys/time.h>
 #endif