Input: adp5588-keys - do not try to disable interrupt 0

Commit dc748812fca0 ("Input: adp5588-keys - add support for pure gpio")
made having interrupt line optional for the device, however it neglected
to update suspend and resume handlers that try to disable interrupts
for the duration of suspend.

Fix this by checking if interrupt number assigned to the i2c device is
not 0 before trying to disable or reenable it.

Fixes: dc748812fca0 ("Input: adp5588-keys - add support for pure gpio")
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/keyboard/adp5588-keys.c

···
 {
 	struct i2c_client *client = to_i2c_client(dev);
 
-	disable_irq(client->irq);
+	if (client->irq)
+		disable_irq(client->irq);
 
 	return 0;
 }
···
 {
 	struct i2c_client *client = to_i2c_client(dev);
 
-	enable_irq(client->irq);
+	if (client->irq)
+		enable_irq(client->irq);
 
 	return 0;
 }