ipvlan: consolidate TSO flags using NETIF_F_ALL_TSO

This will ensure that any new TSO related flags added (which
would be part of ALL_TSO mask and IPvlan driver doesn't need
to update every time new flag gets added.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>