[MIPS] Fix pb1200/irqmap.c and apply some missed patches

    
pb1200/irqmap.c had been broken a while due to non-named initializer
and had missed some recent IRQ related changes.  Apply these commits
to this file.
    
[MIPS] IRQ cleanups
commit 1603b5ac
[MIPS] use generic_handle_irq, handle_level_irq, handle_percpu_irq
commit 1417836e
[MIPS] Compile __do_IRQ() when really needed
commit e77c232c

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>