m68knommu: general interrupt controller for ColdFire 532x parts

The ColdFire 532x family of parts uses 2 of the same INTC interrupt
controlers used in the ColdFire 520x family. So modify the code to
support both parts. The extra code for the second INTC controler in
the case of the 520x is easily optimized away to nothing.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>