Update to kernel header v3.18.3.

Bug: 19127803
Change-Id: I1e00b613153b691fe960b6e080d498f0f65f33b7
diff --git a/original/uapi/linux/xfrm.h b/original/uapi/linux/xfrm.h
index 25e5dd9..02d5125 100644
--- a/original/uapi/linux/xfrm.h
+++ b/original/uapi/linux/xfrm.h
@@ -328,6 +328,8 @@
 	XFRMA_SPD_UNSPEC,
 	XFRMA_SPD_INFO,
 	XFRMA_SPD_HINFO,
+	XFRMA_SPD_IPV4_HTHRESH,
+	XFRMA_SPD_IPV6_HTHRESH,
 	__XFRMA_SPD_MAX
 
 #define XFRMA_SPD_MAX (__XFRMA_SPD_MAX - 1)
@@ -347,6 +349,11 @@
 	__u32 spdhmcnt;
 };
 
+struct xfrmu_spdhthresh {
+	__u8 lbits;
+	__u8 rbits;
+};
+
 struct xfrm_usersa_info {
 	struct xfrm_selector		sel;
 	struct xfrm_id			id;