cpufreq: schedutil: Check SCHED_CPUFREQ_CONTINUE before changing frequency

There is no need to change cluster frequency if there are still other
notifications pending for the cluster. Check SCHED_CPUFREQ_CONTINUE
to check when final frequency adjustment should be made.

Change-Id: Ie6c7941eb1fdad5930844ec5022bdfae8923ce68
Signed-off-by: Kyle Yan <kyan@codeaurora.org>