net: stmmac: intel-plat: remove eee_usecs_rate and hardware write

net: stmmac: intel-plat: remove eee_usecs_rate and hardware write

Remove the write to GMAC_1US_TIC_COUNTER for two reasons:

1. during initialisation or reinitialisation of the DWMAC core, the
   core is reset, which sets this register back to its default value.
   Writing it prior to stmmac_dvr_probe() has no effect.

2. Since commit 8efbdbfa9938 ("net: stmmac: Initialize
   MAC_ONEUS_TIC_COUNTER register"), GMAC4/5 core code will set
   this register based on the rate of plat->stmmac_clk. This clock
   is fetched by devm_stmmac_probe_config_dt(), and plat->clk_ptp_rate
   will be set to its rate profided a "ptp_ref" clock is not provided.
   In any case, Marek's commit will set the effectual value of this
   register.

Therefore, dwmac-intel-plat.c writing GMAC_1US_TIC_COUNTER serves no
useful purpose and can be removed.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1u3Vuq-000E7s-5Y@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>