ixgbe: Add upper limit to ring features

We are currently using indices to indicate the upper limit on a ring
feature.  However since we can switch back and forth on features such as
DCB and that has effects on other features such as RSS it is preferable to
instead store the upper limit separate from the current value for the
number of rings related to the feature.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>