sched/pelt: [HACK] Make PELT trace points unconditional

This is a temporary hack.

Currently trace points for PELT are only triggered when the PELT metrics
consumed by the scheduler are actually updated, i.e. util_avg. This
means no updates if no 1 ms boundary is being crossed by the update.
When reconstructing the PELT signal based on this data, the peak PELT
value can therefore be up to 1 ms worth of PELT accumulation off (23 in
absolute terms). This leads to a discrepancy that causes test cases to
fail.

This patch ensures that trace events are always emitted even if the
metrics haven't been updated which should allow accurate reconstruction
of the PELT signals.