tpm2_i2c_nuvoton: add irq validity check

In 570a3609 IRQ path is incorrectly always exercised while it should be
exercised only when there is an IRQ number allocated. This commit
reverts the old behavior.

[[e-mail]: updated description]

Fixes: 570a36097f3 ("tpm: drop 'irq' from struct tpm_vendor_specific")
Signed-off-by: Andrew Zamansky <[e-mail]>
Reviewed-by: Jarkko Sakkinen <[e-mail]>
Signed-off-by: Jarkko Sakkinen <[e-mail]>

drivers/char/tpm/tpm_i2c_nuvoton.c

···
 	 *   TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
 	 * The IRQ should be set in the i2c_board_info (which is done
 	 * automatically in of_i2c_register_devices, for device tree users */
-	chip->flags |= TPM_CHIP_FLAG_IRQ;
 	priv->irq = client->irq;
-
-	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+	if (client->irq) {
 		dev_dbg(dev, "%s() priv->irq\n", __func__);
 		rc = devm_request_irq(dev, client->irq,
 				      i2c_nuvoton_int_handler,
···
 		if (rc) {
 			dev_err(dev, "%s() Unable to request irq: %d for use\n",
 				__func__, priv->irq);
-			chip->flags &= ~TPM_CHIP_FLAG_IRQ;
 			priv->irq = 0;
 		} else {
+			chip->flags |= TPM_CHIP_FLAG_IRQ;
 			/* Clear any pending interrupt */
 			i2c_nuvoton_ready(chip);
 			/* - wait for TPM_STS==0xA0 (stsValid, commandReady) */