Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/linux/rds.h b/libc/kernel/uapi/linux/rds.h
index cfb0a3b..c726f54 100644
--- a/libc/kernel/uapi/linux/rds.h
+++ b/libc/kernel/uapi/linux/rds.h
@@ -45,6 +45,8 @@
 #define RDS_CMSG_MASKED_ATOMIC_FADD 8
 #define RDS_CMSG_MASKED_ATOMIC_CSWP 9
 #define RDS_CMSG_RXPATH_LATENCY 11
+#define RDS_CMSG_ZCOPY_COOKIE 12
+#define RDS_CMSG_ZCOPY_COMPLETION 13
 #define RDS_INFO_FIRST 10000
 #define RDS_INFO_COUNTERS 10000
 #define RDS_INFO_CONNECTIONS 10001
@@ -197,6 +199,11 @@
 #define RDS_RDMA_CANCELED 2
 #define RDS_RDMA_DROPPED 3
 #define RDS_RDMA_OTHER_ERROR 4
+#define RDS_MAX_ZCOOKIES 8
+struct rds_zcopy_cookies {
+  __u32 num;
+  __u32 cookies[RDS_MAX_ZCOOKIES];
+};
 #define RDS_RDMA_READWRITE 0x0001
 #define RDS_RDMA_FENCE 0x0002
 #define RDS_RDMA_INVALIDATE 0x0004