MIPS: Alchemy: chain IRQ controllers to MIPS IRQ controller

IC and GPIC are now chain handlers of the traditional MIPS IRQ controller.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2933/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>