sh: provide generic arch_debugfs_dir.

While sh previously had its own debugfs root, there now exists a
common arch_debugfs_dir prototype, so we switch everything over to
that.  Presumably once more architectures start making use of this
we'll be able to just kill off the stub kdebugfs wrapper.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/kdebugfs.c

@@ -0,0 +1,16 @@
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+
+struct dentry *arch_debugfs_dir;
+EXPORT_SYMBOL(arch_debugfs_dir);
+
+static int __init arch_kdebugfs_init(void)
+{
+	arch_debugfs_dir = debugfs_create_dir("sh", NULL);
+	if (!arch_debugfs_dir)
+		return -ENOMEM;
+
+	return 0;
+}
+arch_initcall(arch_kdebugfs_init);