cpufreq: interactive: fix boosting logic

35a84de cpufreq: interactive: apply above_hispeed_delay to each step above hispeed

caused the speed choice logic to osciallate between boosting and not boosting.
Add back code to ensure speed does not drop below boost frequency while
boosting.

Change-Id: Id420068480fcc7f5c4989ff523e2a8d22e2f4db2
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Git-Commit: e792d75feabaeb867b618bac8a9b0a77035ab4f9
Git-Repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Dilip Gudlur <dgudlur@codeaurora.org>