MIPS: Kconfig: Add missing MIPS_CPS dependencies to PM and cpuidle

The MIPS_CPS_PM and MIPS_CPS_CPUIDLE implementation should depend
on the MIPS_CPS symbol to avoid the following build problem

arch/mips/kernel/pm-cps.c: In function 'cps_pm_enter_state':
arch/mips/kernel/pm-cps.c:164:26: error: 'cpu_coherent_mask' undeclared
(first use in this function)
cpumask_clear_cpu(cpu, &cpu_coherent_mask);
                            ^
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/7798/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>