net: stmmac: remove GMAC_1US_TIC_COUNTER definition

GMAC_1US_TIC_COUNTER is now no longer used, so remove the definition.
This was duplicated by GMAC4_MAC_ONEUS_TIC_COUNTER further down in the
same file.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1u3Vv0-000E87-DQ@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>