[POWERPC] 85xxCDS: Delay 8259 cascade hookup.

The interrupts of an E100 card inserted in PCI slot 4 may be on at bootup.
The resulting interrupt flood interacts with the 8259 cascade handler and
prevents proper boot up. There is a quirk for the E100 that will disable
the E100's interrupts but to use it, the 8259 cascade hookup must be
delayed until after the quirk has run. This patch delays the 8259 cascade
hookup by registering a device_initcall() which runs after the PCI quirk
for the E100.

Signed-off-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>