net: enetc: read 64-bit statistics from port MAC counters

net: enetc: read 64-bit statistics from port MAC counters

The counters of port MAC are all 64-bit registers, and the statistics of
ethtool are u64 type, so replace enetc_port_rd() with enetc_port_rd64()
to read 64-bit statistics.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250627021108.3359642-4-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>