net/ixgbe: fix statistics in flow control mode

net/ixgbe: fix statistics in flow control mode

The register autoneg can't be updated synchronously with flow control
mode setting in the state of port start, so NIC statistics error occurs.
AUTO_NEG Advt register should be updated by ixgbe_setup_fc() when
enabling flow control.
The patch fixes the issue.

Fixes: a524f550da6e ("net/ixgbe: fix flow control mode setting")
Cc: stable@dpdk.org
Signed-off-by: Guinan Sun <guinanx.sun@intel.com>
Reviewed-by: Wei Zhao <wei.zhao1@intel.com>