ARM: clps711x: Cleanup IRQ handling

This patch contains two changes:
- Removed unused definitions from mach/irqs.h
- Do not mask interrupts in ack procedure, because we have separate
  intX_mask procedure for do it and actually these 2 functions are
  called sequentially

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>