Documentation: networking: ti-cpsw: correct cbs parameters for Eth1 100Mb

If set cbs parameters calculated for 1000Mb, but use on 100Mb port
w/o h/w offload (for cpsw offload it doesn't matter), it works
incorrectly. According to the example and testing board, second port
is 100Mb interface. Correct them on recalculated for 100Mb interface.
It allows to use the same command for CBS software implementation for
board in example.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>