scsi: fcoe: Fix I/O path allocation

ixgbe_fcoe_ddp_setup() can be called from the main I/O path and is called
with a spin_lock held, so we have to use GFP_ATOMIC allocation instead of
GFP_KERNEL.

Link: https://lore.kernel.org/r/1596831813-9839-1-git-send-email-michael.christie@oracle.com


cc: Hannes Reinecke <hare@suse.de>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>