Revert "net/mlx5e: E-Switch, Initialize eswitch only if eswitch manager"

This reverts commit 5f5991f3.

With the original commit, eswitch instance will not be initialized for
a function which is vport group manager but not eswitch manager such as
host PF on SmartNIC (BlueField) card. This will result in a kernel crash
when such a vport group manager is trying to access vports in its group.
E.g, PF vport manager (not eswitch manager) tries to configure the MAC
of its VF vport, a kernel trace will happen similar as bellow:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
 ...
 RIP: 0010:mlx5_eswitch_get_vport_config+0xc/0x180 [mlx5_core]
 ...

Fixes: 5f5991f3 ("net/mlx5e: E-Switch, Initialize eswitch only if eswitch manager")
Signed-off-by: Bodong Wang <bodong@mellanox.com>
Reported-by: Yuval Avnery <yuvalav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>