net: wget: drop Content-Length processing

net: wget: drop Content-Length processing

We don't do anything with Content-Length except a debug print, and the
strict_strtoul() call is incorrect (it always returns -EINVAL and leaves
content_length to zero due to the presence of trailing characters after
the decimal valuoe of Content-Length). So let's just drop this piece of
code.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>