clk: socfpga: stratix10: fix the divider for the emac_ptp_free_clk

The fixed divider the emac_ptp_free_clk should be 2, not 4.

Fixes: 07afb8db ("clk: socfpga: stratix10: add clock driver for
Stratix10 platform")
Cc: stable@vger.kernel.org
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Link: https://lore.kernel.org/r/20200831202657.8224-1-dinguyen@kernel.org


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