ice: rename switchdev to eswitch

Eswitch is used as a prefix for related functions. Main structure
storing all data related to eswitch should also be named as eswitch
instead of ice_switchdev_info. Rename it.

Also rename switchdev to eswitch where the context is not about eswitch
mode.

::uplink_netdev was changed to netdev for simplicity. There is no other
netdev in function scope so it is obvious.

Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Piotr Raczynski <piotr.raczynski@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>