[SCSI] be2iscsi: Format the MAC_ADDR with sysfs_format_mac.

The MAC_ADDR stored in driver private structure is of
unsigned char data type but strlcpy parameters is of
signed char data type. This conversion of data types
lead to change in the value.This changed value is passed
to the upper layer and junk characters were displayed
when "iscsiadm -m iface" command was run.

In case of iSCSI boot, since the the MAC_ADDR was coming
junk the boot was also not working

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>