sched: Update WALT stats also in boosted_cpu_util()

The schedutil is calling twice into the scheduler while querying
the load of each CPU. The cpu_util_freq() is called first to
get the CPU un-boosted load and WALT stats. Then boosted_cpu_util()
is called to get the boosted CPU load. This results in doing the
the same calculations twice in the scheduler and printing
sched_load_to_gov trace point twice. Fix this inefficiency by
changing boosted_cpu_util() to update WALT stats along with
boosted CPU load.

Change-Id: Ia825cafca6a25c56b0edb1ae8c55e7c7277f2968
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
[satyap@codeaurora.org: trivial merge conflict resolution]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>