Update kernel headers to v3.14.

Other changes:
- Modify update_all.py to skip ion header files when importing into aosp.
- Fix generate_uapi_headers.sh to handle imports from a linux-stable kernel.

Change-Id: I1ad81b9ccb063c21740f9875f2cc1238052cd4b3
diff --git a/libc/kernel/uapi/asm-generic/poll.h b/libc/kernel/uapi/asm-generic/poll.h
index 45d2c94..7faa0b8 100644
--- a/libc/kernel/uapi/asm-generic/poll.h
+++ b/libc/kernel/uapi/asm-generic/poll.h
@@ -48,11 +48,12 @@
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif
 #define POLLFREE 0x4000
+#define POLL_BUSY_LOOP 0x8000
 struct pollfd {
- int fd;
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+ int fd;
  short events;
  short revents;
 };
-#endif
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
+#endif