uboot-fritz4040: update package to 2018-12-09

uboot-fritz4040: update package to 2018-12-09

This patch updates the uboot-fritz4040 package to the latest version.
The portability and private-libgcc patches, as well as the
upload-to-f4040.sh script have been added to the upstream repository.
Furthermore, the upload-to-f4040 has been updated to take the first
parameter as the file it is supposed to flash, otherwise it defaults
to the previous "uboot-fritz4040.bin". Furthermore the error messages
have been improved and ftp will now dump some "progress information"
to the user's console.

Also included is support for gcc 8+ and a fix for the obnoxous error
that currently breaks the builders:
| fritz/src/lzma2eva.c:23:30: fatal error: zlib.h: No such file or directory

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
(backported from 5beedcddc3ad2c6f92c24ce2655a84524ca26594)