PM / devfreq: exynos-events: change matching code during probe

The patch changes the way how the 'ops' gets populated for different
device versions. The matching function now uses 'of_device_id' in order
to identify the device type.

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>