net/mlx5: E-Switch, Setup all vports' metadata to support peer miss rule

In merged eswitch configuration, peer miss rule is setup for all
vports. If metadata is enabled, peer miss rule with metadata matching
will be configured instead of source port matching; however, some
vports that have not yet been enabled don't have default_metadata
setup and their default_metadata will be zero.

Hence, setup/cleanup default metadata for all vports when eswitch moves
in/out of offloads mode.

Fixes: 133dcfc5 ("net/mlx5: E-Switch, Alloc and free unique metadata for match")
Signed-off-by: Vu Pham <vuhuong@mellanox.com>
Reviewed-by: Bodong Wang <bodong@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>