Input: elants_i2c - fix division by zero if firmware reports zero phys size

Touchscreen firmware of ASUS Transformer TF700T reports zeros for the phys
size. Hence check whether the size is zero and don't set the resolution in
this case.

Reported-by: Jasper Korten <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: digetx

drivers/input/touchscreen/elants_i2c.c

@@ -1441,7 +1441,7 @@ static int elants_i2c_probe(struct i2c_client *client,
 
 	touchscreen_parse_properties(ts->input, true, &ts->prop);
 
-	if (ts->chip_id == EKTF3624) {
+	if (ts->chip_id == EKTF3624 && ts->phy_x && ts->phy_y) {
 		/* calculate resolution from size */
 		ts->x_res = DIV_ROUND_CLOSEST(ts->prop.max_x, ts->phy_x);
 		ts->y_res = DIV_ROUND_CLOSEST(ts->prop.max_y, ts->phy_y);