MIPS: Add SCHED_HRTICK support

MIPS: Add SCHED_HRTICK support

We have HIGH_RES_TIMERS to support SCHED_HRTICK. But SCHED_HRTICK is in
kernel/Kconfig.hz where HZ values unsuitable for MIPS are defined. So we
simply add this config in arch/mips/Kconfig as opposed to including the
whole kernel/Kconfig.hz.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: macro@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9473/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>