net: ftgmac100: depend on NET

net: ftgmac100: depend on NET

FTGMAC100 enables drivers/net/ftgmac100.c which uses
PHY_INTERFACE_MODE_NCSI, which is defined only when PHY_NCSI is enabled.
Therefore FTGMAC100 depends on PHY_NCSI. However adding such a
dependency causes a "recursive dependency detected!" message, so
add a dependency on NET instead (PHY_NCSI depends on NET).
All in all, either the stack is NET and FTGMAC100 can be enabled,
or it is NET_LWIP (or NO_NET) and it cannot.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>