octeontx2-pf: mcs: Offload extended packet number(XPN) feature

The macsec hardware block supports XPN cipher suites also.
Hence added changes to offload XPN feature. Changes include
configuring SecY policy to XPN cipher suite, Salt and SSCI values.
64 bit packet number is passed instead of 32 bit packet number.

Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>