sata_rcar: fix deferred probing

The driver overrides the error codes returned by platform_get_irq() to
-EINVAL, so if it returns -EPROBE_DEFER, the driver would fail the probe
permanently instead of the deferred probing. Switch to propagating the
error code upstream, still checking/overriding IRQ0 as libata regards it
as "no IRQ" (thus polling) anyway...

Fixes: 9ec36cafe43b ("of/irq: do irq resolution in platform_get_irq")
Reviewed-by: Simon Horman <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Sergei Shtylyov <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/ata/sata_rcar.c

···
 	int ret = 0;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0)
+	if (irq < 0)
+		return irq;
+	if (!irq)
 		return -EINVAL;
 
 	priv = devm_kzalloc(dev, sizeof(struct sata_rcar_priv), GFP_KERNEL);