global: Avoid indirect inclusion of <env.h> from <net.h>

global: Avoid indirect inclusion of <env.h> from <net.h>

Now that env_get_ip() has been removed, the include file <net.h> does
not need anything from <env.h>. Furthermore, include/env.h itself
includes other headers which can lead to longer indirect inclusion
paths. To prepare to remove <env.h> from <net.h> fix all of the
remaining places which had relied on this indirect inclusion to instead
include <env.h> directly.

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org> # net/lwip
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Tom Rini <trini@konsulko.com>