net: stmmac: Drop redundant dwxgmac_tc_ops variable

dwmac510_tc_ops and dwxgmac_tc_ops are completely identical,
keep dwmac510_tc_ops to provide better backward compatibility.

Signed-off-by: Furong Xu <0x1207@gmail.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Link: https://patch.msgid.link/20241212033325.282817-1-0x1207@gmail.com


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