Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/linux/lightnvm.h b/libc/kernel/uapi/linux/lightnvm.h
index 996d873..b3ac317 100644
--- a/libc/kernel/uapi/linux/lightnvm.h
+++ b/libc/kernel/uapi/linux/lightnvm.h
@@ -58,13 +58,21 @@
   __u32 lun_begin;
   __u32 lun_end;
 };
+struct nvm_ioctl_create_extended {
+  __u16 lun_begin;
+  __u16 lun_end;
+  __u16 op;
+  __u16 rsv;
+};
 enum {
   NVM_CONFIG_TYPE_SIMPLE = 0,
+  NVM_CONFIG_TYPE_EXTENDED = 1,
 };
 struct nvm_ioctl_create_conf {
   __u32 type;
   union {
     struct nvm_ioctl_create_simple s;
+    struct nvm_ioctl_create_extended e;
   };
 };
 enum {