hv_netvsc: simplify receive side calling arguments

The calls up from the napi poll reading the receive ring had many
places where an argument was being recreated. I.e the caller already
had the value and wasn't passing it, then the callee would use
known relationship to determine the same value. Simpler and faster
to just pass arguments needed.

Also, add const in a couple places where message is being only read.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>