net: wget: Add interface to issue wget_requests using wget_http_info

net: wget: Add interface to issue wget_requests using wget_http_info

Declare and define a global default struct wget_http_info
and an interface to issue wget requests providing a custom
struct wget_http_info. This code is common to legacy wget
and lwip wget. The idea is that the command wget should use
the default wget_http_info and other internal u-boot code
can call wget_request with their own wget_http_info struct.

Signed-off-by: Adriano Cordova <adrianox@gmail.com>