cpufreq: interactive: don't handle transition notification if not enabled

If multiple governors are in use then avoid processing frequency transition
notifications for CPUs on which the interactive governor is not enabled.

Change-Id: Ibd75255b921d887501a64774a8c4f62302f2d4e4
Reported-by: Francisco Franco <francisco.franco@cloudcar.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Git-Commit: 8e2dfe161140c53bb79a8b2a87a38ff6e2e8a8a9
Git-Repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Dilip Gudlur <dgudlur@codeaurora.org>