Input: force feedback - fix function name in comment

Function name is input_ff_destroy() and not input_ff_free()

Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c
index 72c63e5..3d7816c 100644
--- a/drivers/input/ff-core.c
+++ b/drivers/input/ff-core.c
@@ -353,7 +353,7 @@
 EXPORT_SYMBOL_GPL(input_ff_create);
 
 /**
- * input_ff_free() - frees force feedback portion of input device
+ * input_ff_destroy() - frees force feedback portion of input device
  * @dev: input device supporting force feedback
  *
  * This function is only needed in error path as input core will