soc/tegra: pmc: Fail to allocate more than one wake IRQ

The code currently doesn't support allocating more than one wake IRQ at
a time. Detect this situation and error out. Also make sure to output a
warning when that happens to help track down callers.
Reviewed-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

drivers/soc/tegra/pmc.c

@@ -1863,6 +1863,9 @@ static int tegra_pmc_irq_alloc(struct irq_domain *domain, unsigned int virq,
 	unsigned int i;
 	int err = 0;
 
+	if (WARN_ON(num_irqs > 1))
+		return -EINVAL;
+
 	for (i = 0; i < soc->num_wake_events; i++) {
 		const struct tegra_wake_event *event = &soc->wake_events[i];