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/usb/host/whci/hcd.c b/drivers/usb/host/whci/hcd.c
index f599f89..1569afd 100644
--- a/drivers/usb/host/whci/hcd.c
+++ b/drivers/usb/host/whci/hcd.c
@@ -273,6 +273,8 @@
 		goto error_wusbhc_b_create;
 	}
 
+	whc_dbg_init(whc);
+
 	return 0;
 
 error_wusbhc_b_create:
@@ -296,6 +298,7 @@
 	struct whc *whc = wusbhc_to_whc(wusbhc);
 
 	if (usb_hcd) {
+		whc_dbg_clean_up(whc);
 		wusbhc_b_destroy(wusbhc);
 		usb_remove_hcd(usb_hcd);
 		wusbhc_destroy(wusbhc);