xhci: Add defines for hardcoded slot states

This needs to be added to the stable trees back to 2.6.34 to support an
upcoming bug fix.

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
diff --git a/drivers/usb/host/xhci-dbg.c b/drivers/usb/host/xhci-dbg.c
index 2e04861..1f50b44 100644
--- a/drivers/usb/host/xhci-dbg.c
+++ b/drivers/usb/host/xhci-dbg.c
@@ -438,13 +438,13 @@
 	struct xhci_slot_ctx *slot_ctx = xhci_get_slot_ctx(xhci, ctx);
 
 	switch (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state))) {
-	case 0:
+	case SLOT_STATE_ENABLED:
 		return "enabled/disabled";
-	case 1:
+	case SLOT_STATE_DEFAULT:
 		return "default";
-	case 2:
+	case SLOT_STATE_ADDRESSED:
 		return "addressed";
-	case 3:
+	case SLOT_STATE_CONFIGURED:
 		return "configured";
 	default:
 		return "reserved";