hv_netvsc: Fix the variable sizes in ipsecv2 and rsc offload

These fields in struct ndis_ipsecv2_offload and struct ndis_rsc_offload
are one byte according to the specs. This patch defines them with the
right size. These structs are not in use right now, but will be used soon.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>