net: phy: nxp-c45-tja11xx: add MACsec statistics

Add MACsec statistics callbacks.
The statistic registers must be set to 0 if the SC/SA is
deleted to read relevant values next time when the SC/SA is used.

Signed-off-by: Radu Pirea (NXP OSS) <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Radu Pirea (NXP OSS)