cpufreq: interactive: Optimize sync_freq implementation

Don't let frequency drop below sync_freq if either load or
frequency among other cpus is above a certain threshold,
not necessarily both.

Change-Id: Iada28e08e812498e16d5189b309a7314f88814dd
cpufreq: interactive: Honor changed minimum frequency

This saves a few cycles in the timer routine.

Change-Id: If6df54acd5ff098b04c30b25aa6fc2078385040f
zwliew: modify for previous driver commits
cpufreq: interactive: Use parts of native boost routine

Not all governors are created equal. Set boostpulse_endtime
and floor_freq to smoothen the timer routine.

Change-Id: I3e0a513755fc98037bc9b555de716b3ff08b1e39
zwliew: structural changes for previous driver changes
cpufreq: interactive: Use frequency dependent per cpu timings

This allows in-depth testing of the timer routine.

Change-Id: I87f05baeba796f7053c388cc50e0c51fa06b55a5
zwliew: structural changes for previous driver changes
cpufreq: interactive: Honor boosted state when entering idle

The old logic didn't take the boosted state in account. Just
leave the comment intact because our temporary min is not
the regular policy->min it refers to.
cpufreq: interactive: fix compiling warnings
cpufreq: interactive: Initialize spinlocks

These were missing in commit 8fbac318173082918312d6a4ceacf63376797c52,
"cpufreq: interactive: Use frequency dependent per cpu timings".