cpufreq: interactive: fix compiling warnings

The gcc warns like:

  cpufreq_interactive.c:745:6: warning: operation on 'ret' may be undefined [-Wsequence-point]

It was introduced by commit cf0fad49d17cb8273ce555dd5b7afab67d7923bf.

Since sprintf(...) just return 1 (one character) in this case, ret should not changed.
Just discarding the result of sprintf(...) leads to the result that
the committer of cf0fad49d17cb8273ce555dd5b7afab67d7923bf wants.

Change-Id: Ifed1cef6d6a31c3ed23dad03a567b3b9eddf3a57
Signed-off-by: Chih-Wei Huang <cwhuang@android-x86.org>
Git-commit: 0715d10b9e6c04327adb189e13ecd6a3c2df48ce
Git-Repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Revert timer start modification

commit f8b276565ce95bd788af0fc8d060f92632590a40
(cpufreq: Sync on thread migration optimizations)
introduced a change to cpufreq_interactive_timer_start() in order
to reschedule the timer differently based on whether min or max
is changed. A better way is to reschedule the timer only when
necessary.

Revert timer start modification in preparation for the final fix.

Change-Id: I13f3b75a6eee03ac6380c24db899806a9bfbc96a
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>