drivers: net: cpsw: add support for reading mac address from efuse

Different TI platforms has to read with different combination to
get the mac address from efuse. So add support to read mac address
based on machine/device compatibles.

The code is taken from Linux drivers/net/ethernet/ti/cpsw-common.c
done by Tony Lindgren.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>