ixgbevf: create function for all of ring init

This patch creates new functions for ring initialization,
ixgbevf_configure_tx_ring() and ixgbevf_configure_rx_ring(). The work done
in these function previously was spread between several other functions and
this change should hopefully lead to greater readability and make the code
more like ixgbe.  This patch also moves the placement of some older functions
to avoid having to write prototypes.  It also promotes a couple of debug
messages to errors.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Don Skidmore <donald.c.skidmore@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>