ixgbe: fix race when setting advertised speed

Following commands:

modprobe ixgbe
ifconfig ethX up
ethtool -s ethX advertise 0x020

can lead to "setup link failed with code -14" error due to the setup_link
call racing with the SFP detection routine in the watchdog.

This patch resolves this issue by protecting the setup_link call with check
for __IXGBE_IN_SFP_INIT.

Reported-by: Scott Harrison <scoharr2@cisco.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>