audit: allow matching on obj_uid

Allow syscall exit filter matching based on the uid of the owner of an
inode used in a syscall.  aka:

auditctl -a always,exit -S open -F obj_uid=0 -F perm=wa

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 67b66c3..55cb3da 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -223,6 +223,7 @@
 #define AUDIT_PERM	106
 #define AUDIT_DIR	107
 #define AUDIT_FILETYPE	108
+#define AUDIT_OBJ_UID	109
 
 #define AUDIT_ARG0      200
 #define AUDIT_ARG1      (AUDIT_ARG0+1)