irq_domain: convert microblaze from irq_host to irq_domain

Trivial change, microblaze doesn't use irq remapping yet.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Thomas Gleixner <tglx@linutronix.de>

arch/microblaze/kernel/irq.c

@@ -51,7 +51,7 @@ next_irq:
 
 /* MS: There is no any advance mapping mechanism. We are using simple 32bit
   intc without any cascades or any connection that's why mapping is 1:1 */
-unsigned int irq_create_mapping(struct irq_host *host, irq_hw_number_t hwirq)
+unsigned int irq_create_mapping(struct irq_domain *host, irq_hw_number_t hwirq)
 {
 	return hwirq + IRQ_OFFSET;
 }