On pSeries systems, the firmware tells us a list of interrupt numbers
that we should enable in order to detect various error conditions.
When we get one of these interrupts we are supposed to call the
firmware, which will work out and tell us what the error was and
possibly also fix it.

We were not correctly parsing the property values that tell us which
interrupts need to be handled in this fashion.  This patch fixes it.
It exports prom_n_intr_cells from prom.c since that is needed to do
the parsing properly.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>