msm_rq_stats: added support enable load calculation on demand

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c
sched: added time-based average load