MIPS: i8259: Mark cascade interrupt non-threaded

MIPS: i8259: Mark cascade interrupt non-threaded

Cascade interrupts cannot be threaded.

Signed-off-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1314370804-21266-1-git-send-email-liming.wang@windriver.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2770/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>