Highlight that NET really is the legacy networking stack by renaming the
option to NET_LEGACY.
This requires us to add an SPL_NET_LEGACY alias to SPL_NET as otherwise
CONFIG_IS_ENABLED(NET_LEGACY) will not work for SPL.
The "depends on !NET_LWIP" for SPL_NET clearly highlights that it is
using the legacy networking app so this seems fine to do.
This also has the benefit of removing potential confusion on NET being a
specific networking stack instead of "any" network stack.
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>