oprofilefs_mkdir() doesn't need superblock argument

it's always equal to ->d_sb of the second argument (parent dentry),
due to either being literally that, or ->d_sb of parent's parent.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/alpha/oprofile/common.c b/arch/alpha/oprofile/common.c
index d79bf68..a44608b 100644
--- a/arch/alpha/oprofile/common.c
+++ b/arch/alpha/oprofile/common.c
@@ -115,7 +115,7 @@
 		char buf[4];
 
 		snprintf(buf, sizeof buf, "%d", i);
-		dir = oprofilefs_mkdir(root->d_sb, root, buf);
+		dir = oprofilefs_mkdir(root, buf);
 
 		oprofilefs_create_ulong(root->d_sb, dir, "enabled", &ctr[i].enabled);
                 oprofilefs_create_ulong(root->d_sb, dir, "event", &ctr[i].event);