x86/intel_rdt: Fix memory leak on mount failure

If mount fails, the kn_info directory is not freed causing memory leak.

Add the missing error handling path.

Fixes: 4e978d06 ("x86/intel_rdt: Add "info" files to resctrl file system")
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: vikas.shivappa@intel.com
Cc: andi.kleen@intel.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1498503368-20173-3-git-send-email-vikas.shivappa@linux.intel.com

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

@@ -856,11 +856,13 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
 	dentry = kernfs_mount(fs_type, flags, rdt_root,
 			      RDTGROUP_SUPER_MAGIC, NULL);
 	if (IS_ERR(dentry))
-		goto out_cdp;
+		goto out_destroy;
 
 	static_branch_enable(&rdt_enable_key);
 	goto out;
 
+out_destroy:
+	kernfs_remove(kn_info);
 out_cdp:
 	cdp_disable();
 out: