irqdomain: Clean up aftermath of irq_domain refactoring

After refactoring the irqdomain code, there are a number of API
functions that are merely empty wrappers around core code. Drop those
wrappers out of the C file and replace them with static inlines in the
header.

Signed-off-by: Grant Likely <grant.likely@linaro.org>

arch/powerpc/platforms/powermac/smp.c

@@ -192,7 +192,7 @@ static int psurge_secondary_ipi_init(void)
 {
 	int rc = -ENOMEM;
 
-	psurge_host = irq_domain_add_nomap(NULL, 0, &psurge_host_ops, NULL);
+	psurge_host = irq_domain_add_nomap(NULL, ~0, &psurge_host_ops, NULL);
 
 	if (psurge_host)
 		psurge_secondary_virq = irq_create_direct_mapping(psurge_host);