sh_eth: remove dependencies from Kconfig

Since dependence on the certain SoCs is no  longer  necessary to compile the
driver, remove the dependency list from its Kconfig entry which is a popular
demand anyway...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>