net/mlx5: support 64-bit for modify field action

net/mlx5: support 64-bit for modify field action

Extend the range of immediate value used in the MODIFY_FIELD action
from 32 to 64 bits to conform to the rte_flow_action_modify_data spec.
Apply appropriate big endian conversion to the immediate value
according to a destination field bit width.

Fixes: 641dbe4fb053 ("net/mlx5: support modify field flow action")
Cc: stable@dpdk.org
Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>