nvmem: imx: scu: correct the fuse word index

nvmem: imx: scu: correct the fuse word index

i.MX8 fuse word row index represented as one 4-bytes word.
Exp:
- MAC0 address layout in fuse:
offset 708: MAC[3] MAC[2] MAC[1] MAC[0]
offset 709: XX     xx     MAC[5] MAC[4]

The original code takes row index * 4 as the offset, this
not exactly match i.MX8 fuse map documentation.

So update code the reflect the truth.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200109104017.6249-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>