common/cpt: fix encryption offset
common/cpt: fix encryption offset

In case of gmac auth the encryption offset should be set to zero.

Fixes: b74652f3a91f ("common/cpt: add microcode interface for encryption")
Fixes: 177b41ceee61 ("common/cpt: add microcode interface for decryption")
Cc: stable@dpdk.org

Signed-off-by: Ankur Dwivedi <ddcd6098b98d6077e8af1e63c839e98d07e002c4@marvell.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk