ixgbe: Combine post-DMA processing of sk_buff fields into single function

This change combines a number of post-DMA Rx packet processing functions
into a single function.  The advantage of this is that it combines most of
the Rx descriptor processing into one spot so it should all be warm in the
cache.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>