[SCSI] libfcoe: move logging macros into the local libfcoe.h header file

libfcoe kernel module debug macros will used by the fcoe transport code
as well when later it gets added.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>