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/setup.c

@@ -51,8 +51,6 @@ void __init setup_arch(char **cmdline_p)
 
 	unflatten_device_tree();
 
-	/* NOTE I think that this function is not necessary to call */
-	/* irq_early_init(); */
 	setup_cpuinfo();
 
 	microblaze_cache_init();