Cpufreq: Added input event hook to ramp up cpu frequency

This will cause switch to maximum opp immediately when user
interaction occurs, i.e. touchscreen input or keypad activity.

Change-Id: I0cfe32479ef62a967f359c1bf57f97eefde7e8f7
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
[bsteuer@quicinc.com: fixed cpu_dbs_info naming, added header]
Signed-off-by: Brian Steuer <bsteuer@codeaurora.org>