ixgbevf: Add lock around ixgbevf_reinit_locked call

The function ixgbevf_reinit_locked() assumes you have the rtnl lock
however we didn't when calling from the service task.  This patch
corrects that.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>