x86: Add a arch directory for x86 under debugfs

Add a directory for x86 arch under debugfs. Can be used to accumulate all
x86 specific debugfs files.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 7266124..32755cd 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -26,6 +26,8 @@
 	unsigned long size;
 };
 
+extern struct dentry *arch_debugfs_dir;
+
 #if defined(CONFIG_DEBUG_FS)
 
 /* declared over in file.c */