switch vfs_mkdir() and ->mkdir() to umode_t

vfs_mkdir() gets int, but immediately drops everything that might not
fit into umode_t and that's the only caller of ->mkdir()...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a184470..b37a0ea 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -760,7 +760,7 @@
  * -> cgroup_mkdir.
  */
 
-static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
 static struct dentry *cgroup_lookup(struct inode *, struct dentry *, struct nameidata *);
 static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
 static int cgroup_populate_dir(struct cgroup *cgrp);
@@ -3846,7 +3846,7 @@
 	return err;
 }
 
-static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	struct cgroup *c_parent = dentry->d_parent->d_fsdata;