ixgbe: pull all Tx init into ixgbe_configure_tx

The Tx init was spread out over ixgbe_configure, ixgbe_configure_tx, and
ixgbe_up_complete.  This change combines all of that into the
ixgbe_configure_tx function in order to simplify the Tx init path.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>