ppc-6xx: fix build failure in flipper-pic.c and hlwd-pic.c

The commit bae1d8f1 (linux-next)

  "irq_domain/powerpc: Use common irq_domain structure instead of irq_host"

made this change:

   -static struct irq_host *flipper_irq_host;
   +static struct irq_domain *flipper_irq_host;

and this change:

   -static struct irq_host *hlwd_irq_host;
   +static struct irq_domain *hlwd_irq_host;

The intent was to change the type, and not the name, but then in a
couple of instances, it looks like the sed to change the irq_domain_ops
name inadvertently also changed the irq_host name where it was not
supposed to, causing build failures.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>