[PATCH] ppc32: Fix mpc8xx watchdog

The CONFIG_8xx_WDT option got broken in the generic hardirq update as ppc32
had its own different request_irq that worked when other arches used
setup_irq.  This is the trivial fix for the problem.

From: Carsten Juttner <carjay@gmx.net>
Signed-off-by: Tom Rini <trini@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>