ixgbevf: Fix AIM (Adaptive Interrupt Moderation)

While fixing up a patch from Alex Duyck to use q_vectors in ring containers
to update the ITR I bungled it and missed actually updating the counters
in the ring container q_vectors.  This patch fixes my mistake and makes
interrupt moderation actually work.

Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>