msm: rq_stats: Calculate load based on current freq limit

Prior to this patch, load has been calculated based on an
initial value of policy.cpuinfo.max_freq. This value may
change for several reasons: userspace settings or thermal
throttling (hello hammerhead!). This results in unreliable
calculations that confuse mpdecision which accesses
/sys/devices/system/cpu/cpu0/rq-stats/* for stats info.
Consider current policy.max to fix this behaviour.

Change-Id: Iae1f2fc7f4aa470f7e80371c1ebcf7be423f51ca
soc: qcom: rq_stats: remove the redundant iowait check

Iowait_time check is redundant and it would lead to heavy load
due to miscaluculation of idle time. Hence remove this check
as iowait will considered based on io_busy flag.

Change-Id: I4dd9f9c79205eca588daea8cc0fe892394a83391
CRs-fixed: 662052
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>
[zwliew: Backport to msm-3.4]
Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>