fcoe: Fix smatch warning in fcoe_fdmi_info function

This patch fixes a smatch warning as below:

smatch warnings:
drivers/scsi/fcoe/fcoe.c:782 fcoe_fdmi_info() warn: 'fdmi' puts 896 bytes on
stack

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Neerav Parikh <Neerav.Parikh@intel.com>
Tested-by: Jack Morgan <jack.morgan@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>