Update to v4.15 kernel headers.

Test: Compiles, boots bullhead/hikey960.
Change-Id: I118beb8b6cac0881b1270f9bf6981959297a41a8
diff --git a/libc/kernel/uapi/linux/xattr.h b/libc/kernel/uapi/linux/xattr.h
index efa99e7..7c098f4 100644
--- a/libc/kernel/uapi/linux/xattr.h
+++ b/libc/kernel/uapi/linux/xattr.h
@@ -56,6 +56,8 @@
 #define XATTR_NAME_SMACKEXEC XATTR_SECURITY_PREFIX XATTR_SMACK_EXEC
 #define XATTR_NAME_SMACKTRANSMUTE XATTR_SECURITY_PREFIX XATTR_SMACK_TRANSMUTE
 #define XATTR_NAME_SMACKMMAP XATTR_SECURITY_PREFIX XATTR_SMACK_MMAP
+#define XATTR_APPARMOR_SUFFIX "apparmor"
+#define XATTR_NAME_APPARMOR XATTR_SECURITY_PREFIX XATTR_APPARMOR_SUFFIX
 #define XATTR_CAPS_SUFFIX "capability"
 #define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX
 #define XATTR_POSIX_ACL_ACCESS "posix_acl_access"