ixgbevf: Drop all dead or unnecessary code

There is a large amount of code present in this driver to support features
that either do no exist or are not supported such ask packet split, DCA, or
RSC.  This patch strips out almost all of that code and in the case of
conditionals based on unused flags I am flatting the code out to just the
path that would have been selected.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>