i.mx: i.mx5: update imx_get_mac_from_fuse function

i.mx: i.mx5: update imx_get_mac_from_fuse function

FEC does not work on the i.mx51/53evk board, it will hangup
In:    serial
Out:   serial
Err:   serial
Net:

After bisect, it due to the following commit:
be252b6 net: imx: Add multi-FEC support for imx_get_mac_from_fuse
has change the imx_get_mac_from_fuse fucntion prototype, but fail
to update i.mx5, here it does it.

After apply this patch, u-boot works again on i.mx51/53 evk boards.

Signed-off-by: Jason Liu <jason.hui@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
Acked-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>