icplus: mdio_write(), remove unnecessary for loop

icplus: mdio_write(), remove unnecessary for loop

At this point the variable j is always set to 7 and the code within
the loop has to run only once anyway.

As suggested by David Miller:
"You can simply this even further since p[7] is what is used here,
and this means len is one, the inner loop therefore executes only
once, and the p[7].field value is not used (it's zero in the table)
and the write to it is completely thrown away."

Signed-off-by: Patrick Kelle <patrick.kelle81@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>