[SCSI] libfcoe: Don't KERN_ERR on netdev notification

This is more of a debug statement. As a KERN_ERR we generate
log entries anytime any netdev goes up or down, so when booting
there are notification log entries for all system interfaces
including 'lo'. This is too much. Let's just log when necessary.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>