net/ixgbe: fix build when vector driver disabled

net/ixgbe: fix build when vector driver disabled

The new functions for Rx and Tx offloads should not be inside the
conditional block for the vector driver, otherwise compile errors occur
when vector driver is disabled. For example:

  ixgbe_ethdev.c:3636:36: error:
	implicit declaration of function ‘ixgbe_get_rx_queue_offloads’;

This shows up as an error when doing ARM builds using meson as the vector
driver is not (yet) enabled for those builds.

Fixes: 51215925a32f ("net/ixgbe: convert to new Tx offloads API")
Fixes: ec3b1124d14d ("net/ixgbe: convert to new Rx offloads API")

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>