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/security/capability.c b/security/capability.c
index 2984ea4..ddd1789 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -148,7 +148,7 @@
 }
 
 static int cap_inode_mkdir(struct inode *inode, struct dentry *dentry,
-			   int mask)
+			   umode_t mask)
 {
 	return 0;
 }