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

Signed-off-by: MassStash <MassStash@gmail.com>