enic: Cleanups in port profile helper code

This patch does the following:
- Introduces a new macro VIC_PROVINFO_ADD_TLV
- Adds a new OS type in vic_generic_prov_os_type
- Changes some vic_provinfo* helper routine args to constants

Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: David Wang <dwang2@cisco.com>
Signed-off-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>