This is now exactly the same as mpc83xx_ipic_init_IRQ, so just use
that directly.

Acked-by: Scott Wood <oss@buserror.net>
Reviewed-by: Timur Tabi <timur@kernel.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Li Yang <leoyang.li@nxp.com>