Update to v5.0 kernel headers.

Test: Builds and boots on taimen.
Change-Id: I13843bf1ab30ea89a50852adc88f2cba8401bded
diff --git a/libc/kernel/uapi/linux/auto_fs.h b/libc/kernel/uapi/linux/auto_fs.h
index 0264b86..9a9dd65 100644
--- a/libc/kernel/uapi/linux/auto_fs.h
+++ b/libc/kernel/uapi/linux/auto_fs.h
@@ -24,7 +24,7 @@
 #define AUTOFS_PROTO_VERSION 5
 #define AUTOFS_MIN_PROTO_VERSION 3
 #define AUTOFS_MAX_PROTO_VERSION 5
-#define AUTOFS_PROTO_SUBVERSION 3
+#define AUTOFS_PROTO_SUBVERSION 4
 #if defined(__ia64__) || defined(__alpha__)
 typedef unsigned long autofs_wqt_t;
 #else