devfreq: exynos-ppmu: simplify parsing event-type from DT

devfreq: exynos-ppmu: simplify parsing event-type from DT

When parsing devicetree, the function of_get_devfreq_events(), for each
device child node, iterates over array of possible events "ppmu_events"
till it finds one matching by node name.  When match is found the
ppmu_events[i] points to element having both the name of the event and
the counters ID.

Each PPMU device child node might have an "event-name" property with the
name of the event, however due to the design of devfreq it must be the
same as the device node name.  If it is not the same, the devfreq client
won't be able to use it via devfreq_event_get_edev_by_phandle().

Since PPMU device child node name must be equal to the "event-name"
property (event-name == ppmu_events[i].name), there is no need to find
the counters ID by the "event-name".  Instead use ppmu_events[i].id
which must be equal to it.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>