ixgbevf: move ring specific stats into ring specific structure

ixgbevf: move ring specific stats into ring specific structure

This patch moves hot-path specific statistics into the ring structure.
This allows us to drop the adapter structure in some functions and should
help with performance.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>