Replace struct sw_net_dev and GETIFLIST with sw_api related struct and call.

Replace struct sw_net_dev with sw_net_device from sw_api.h in order to obtain a
generic list after SWCFG_GETIFLIST call. Also fix bug when retrieving interface
list for lisa implementation.

Signed-off-by: Andreea Hodea <hodea_andreea@yahoo.com>