net: enetc: remove local "priv" variable in enetc_clean_tx_ring()

net: enetc: remove local "priv" variable in enetc_clean_tx_ring()

The "priv" variable is needed in the "check_writeback" scope since
commit c5fbfce6cd85 ("enetc: add hardware timestamping support").

Since commit 863ef1095c5a ("enetc: support PTP Sync packet one-step
timestamping"), we also need "priv" in the larger function scope.

So the local variable from the "if" block scope is not needed, and
actually shadows the other one. Delete it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>