intel_th: gth: Fix a source comment

There's a kerneldoc comment that'd been derived from another one by way
of copying-and-pasting but hadn't been subsequently amended to reflect
the purpose of the function. Fix this.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

drivers/hwtracing/intel_th/gth.c

@@ -465,7 +465,7 @@ static int intel_th_output_attributes(struct gth_device *gth)
 }
 
 /**
- * intel_th_gth_disable() - enable tracing to an output device
+ * intel_th_gth_disable() - disable tracing to an output device
  * @thdev:	GTH device
  * @output:	output device's descriptor
  *