[PATCH] powerpc: fix MPIC OF tree parsing on Apple quad g5

The quad g5 currently doesn't boot due to two problems.  This patch fixes the
first one: Apple new way of doing interrupt specifiers in OF for devices using
the HT APIC isn't properly parsed by the new MPIC driver code.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>