Input: tsc2007 - change warning to debug message if pen GPIO is not defined

Since pen GPIO request is optional, there is no reason to throw dev_warn if
such GPIO is not defined.

Signed-off-by: Svyatoslav Ryhel <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/tsc2007_core.c

···
 	if (ts->gpiod)
 		ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 	else
-		dev_warn(dev, "Pen down GPIO is not specified in properties\n");
+		dev_dbg(dev, "Pen down GPIO is not specified in properties\n");
 
 	return 0;
 }