[PATCH] powerpc: cell interrupt controller updates

The current interrupt controller setup on Cell is done
in a rather ad-hoc way with device tree properties
that are not standardized at all.

In an attempt to do something that follows the OF standard
(or at least the IBM extensions to it) more closely,
we have now come up with this patch. It still provides
a fallback to the old behaviour when we find older firmware,
that hack can not be removed until the existing customer
installations have upgraded.

Cc: hpenner@de.ibm.com
Cc: stk@de.ibm.com
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Milton Miller <miltonm@bga.com>
Cc: benh@kernel.crashing.org
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>