wusb: add debug files for ASL, PZL and DI to the whci-hcd driver

Add asl, pzl and di debugfs files to uwb/uwbN/wusbhc for WHCI host
controller.  These dump the current ASL, PZL and DI buffer.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
diff --git a/drivers/uwb/uwb-debug.c b/drivers/uwb/uwb-debug.c
index ec1b7a4..a6debb9 100644
--- a/drivers/uwb/uwb-debug.c
+++ b/drivers/uwb/uwb-debug.c
@@ -407,3 +407,16 @@
 {
 	debugfs_remove(root_dir);
 }
+
+/**
+ * uwb_dbg_create_pal_dir - create a debugfs directory for a PAL
+ * @pal: The PAL.
+ */
+struct dentry *uwb_dbg_create_pal_dir(struct uwb_pal *pal)
+{
+	struct uwb_rc *rc = pal->rc;
+
+	if (root_dir && rc->dbg && rc->dbg->root_d && pal->name)
+		return debugfs_create_dir(pal->name, rc->dbg->root_d);
+	return NULL;
+}