Input: elants_i2c - zero-extend hardware ID in firmware name

Let's zero-extend hardware id number when forming firmware file name,
to avoid kernel requesting firmware like "elants_i2c_   0.bin", which
is quite unexpected.

Acked-by: Charlie Mooney<charliemooney@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/elants_i2c.c

@@ -699,7 +699,7 @@ static int elants_i2c_fw_update(struct elants_data *ts)
 	char *fw_name;
 	int error;
 
-	fw_name = kasprintf(GFP_KERNEL, "elants_i2c_%4x.bin", ts->hw_version);
+	fw_name = kasprintf(GFP_KERNEL, "elants_i2c_%04x.bin", ts->hw_version);
 	if (!fw_name)
 		return -ENOMEM;