usb: typec: anx7411: fix error checking in anx7411_get_gpio_irq()

This is a minor bug which means that certain error messages are not
printed.

The devm_gpiod_get_optional() function can return either error pointers
or NULL.  It returns error pointers if there is an allocation failure,
or a similar issue.  It returns NULL if no GPIO was assigned to the
requested function.  Print an error in either case.

The gpiod_to_irq() function never returns zero.  It either returns
a positive IRQ number or a negative error code.

Fixes: fe6d8a9c ("usb: typec: anx7411: Add Analogix PD ANX7411 support")
Reviewed-by: Xin Ji <xji@analogixsemi.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YtpDs8VsWIbl/Smd@kiliSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/anx7411.c

@@ -1326,13 +1326,13 @@ static void anx7411_get_gpio_irq(struct anx7411_data *ctx)
 	struct device *dev = &ctx->tcpc_client->dev;
 
 	ctx->intp_gpiod = devm_gpiod_get_optional(dev, "interrupt", GPIOD_IN);
-	if (!ctx->intp_gpiod) {
+	if (IS_ERR_OR_NULL(ctx->intp_gpiod)) {
 		dev_err(dev, "no interrupt gpio property\n");
 		return;
 	}
 
 	ctx->intp_irq = gpiod_to_irq(ctx->intp_gpiod);
-	if (!ctx->intp_irq)
+	if (ctx->intp_irq < 0)
 		dev_err(dev, "failed to get GPIO IRQ\n");
 }