Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/linux/random.h b/libc/kernel/uapi/linux/random.h
index 6ad4f75..3a5fbfd 100644
--- a/libc/kernel/uapi/linux/random.h
+++ b/libc/kernel/uapi/linux/random.h
@@ -27,6 +27,7 @@
 #define RNDADDENTROPY _IOW('R', 0x03, int[2])
 #define RNDZAPENTCNT _IO('R', 0x04)
 #define RNDCLEARPOOL _IO('R', 0x06)
+#define RNDRESEEDCRNG _IO('R', 0x07)
 struct rand_pool_info {
   int entropy_count;
   int buf_size;