Input: fix signedness warning in input_set_keycode()

The dev->getkeycode() method expects unsigned argument.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 240ad39..a3d5485 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -694,7 +694,7 @@
 		      unsigned int scancode, unsigned int keycode)
 {
 	unsigned long flags;
-	int old_keycode;
+	unsigned int old_keycode;
 	int retval;
 
 	if (keycode > KEY_MAX)