xtensa: drop variant IRQ support

If an xtensa core provides an additional IRQ controller it should be
treated as a separate piece of hardware and be driven by an irqchip
driver.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

drivers/irqchip/irq-xtensa-mx.c

@@ -98,14 +98,12 @@ static void xtensa_mx_irq_unmask(struct irq_data *d)
 
 static void xtensa_mx_irq_enable(struct irq_data *d)
 {
-	variant_irq_enable(d->hwirq);
 	xtensa_mx_irq_unmask(d);
 }
 
 static void xtensa_mx_irq_disable(struct irq_data *d)
 {
 	xtensa_mx_irq_mask(d);
-	variant_irq_disable(d->hwirq);
 }
 
 static void xtensa_mx_irq_ack(struct irq_data *d)