power: supply: bq27xxx-i2c: Do not free non existing IRQ

The bq27xxx i2c-client may not have an IRQ, in which case
client->irq will be 0. bq27xxx_battery_i2c_probe() already has
an if (client->irq) check wrapping the request_threaded_irq().

But bq27xxx_battery_i2c_remove() unconditionally calls
free_irq(client->irq) leading to:

[ 190.310742] ------------[ cut here ]------------
[ 190.310843] Trying to free already-free IRQ 0
[ 190.310861] WARNING: CPU: 2 PID: 1304 at kernel/irq/manage.c:1893 free_irq+0x1b8/0x310

Followed by a backtrace when unbinding the driver. Add
an if (client->irq) to bq27xxx_battery_i2c_remove() mirroring
probe() to fix this.

Fixes: 444ff00734f3 ("power: supply: bq27xxx: Fix I2C IRQ race on remove")
Signed-off-by: Hans de Goede <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/supply/bq27xxx_battery_i2c.c

···
 {
 	struct bq27xxx_device_info *di = i2c_get_clientdata(client);
 
-	free_irq(client->irq, di);
+	if (client->irq)
+		free_irq(client->irq, di);
+
 	bq27xxx_battery_teardown(di);
 
 	mutex_lock(&battery_mutex);