intel_th: Enumerate Low Power Path output port type

Trace Hub 2.x adds Low Power Path (LPP) output port type, which provides
a low power mode trace path from sources to PTI or BSSB.

This adds an output subdevice for the LPP port.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
diff --git a/drivers/hwtracing/intel_th/intel_th.h b/drivers/hwtracing/intel_th/intel_th.h
index d44da50..3f45584 100644
--- a/drivers/hwtracing/intel_th/intel_th.h
+++ b/drivers/hwtracing/intel_th/intel_th.h
@@ -103,7 +103,8 @@ enum {
 	GTH_NONE = 0,
 	GTH_MSU,	/* memory/usb */
 	GTH_CTP,	/* Common Trace Port */
-	GTH_PTI = 4,	/* MIPI-PTI */
+	GTH_LPP,	/* Low Power Path */
+	GTH_PTI,	/* MIPI-PTI */
 };
 
 /**