clk: baikal-t1: Fix invalid xGMAC PTP clock divider

Most likely due to copy-paste mistake the divider has been set to 10 while
according to the SoC reference manual it's supposed to be 8 thus having
PTP clock frequency of 156.25 MHz.

Fixes: 353afa3a ("clk: Add Baikal-T1 CCU Dividers driver")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20220929225402.9696-3-Sergey.Semin@baikalelectronics.ru


Signed-off-by: Stephen Boyd <sboyd@kernel.org>