pg-wcom-ls102xa: fix sys counter frequency

A system clock of 66MHz was chosen for the pg-wcom-ls102xa.
Compared to the Evalboard, this corresponds to a reduction of 1/3.
The system counter clock should have been reduced accordingly,
but that was not the case, so we had a system time that was
1/3 behind the real time.

This patch corrects the system counter clock to
8.333MHz = 66.667MHz / 8.

Signed-off-by: Rainer Boschung <rainer.boschung@hitachi-powergrids.com>
Signed-off-by: Aleksandar Gerasimovski <aleksandar.gerasimovski@hitachi-powergrids.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>