arm: renesas: Enable wget command and TCP on all R-Car systems

arm: renesas: Enable wget command and TCP on all R-Car systems

Enable the 'wget' command and TCP protocol support on all Renesas R-Car
systems. This allows users to download content from local HTTP server,
which may sometimes be more accessible than TFTP server. Enable TCP SACK
support to improve download performance.

The usage is similar to the TFTP command. To download file from server
http://192.ser.ver.ip/file/path/on/local/server , invoke wget as follows:
"
=> wget $loadaddr 192.ser.ver.ip:/file/path/on/local/server
"

In case the HTTP server listens on port other than default port 80,
set the 'httpdstp' environment variable to download file from server
http://192.ser.ver.ip:8088/file/path/on/local/server
"
=> env set httpdstp 8088
=> wget $loadaddr 192.ser.ver.ip:/file/path/on/local/server
"

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>