u-boot-tools: drop the hardlink workaround in do_compile

u-boot-tools: drop the hardlink workaround in do_compile

This workaround initially considered a host running git < v2.14, which
does not look realistic if we consider the fairly recent distros in
SANITY_TESTED_DISTROS.

Even in older build machines/distros, one can use buildtools to provide git:

$ ./x86_64-buildtools-extended-nativesdk-standalone-5.0.sh
(...)
$ which git
(...)/buildtools/sysroots/x86_64-pokysdk-linux/usr/bin/git
$ git --version
git version 2.44.0

It is harmless, but still a bit outdated, so remove it.

[RP: the earliest git version on our test builders is ~2.33 so no distros
we currently support would run into this]

Signed-off-by: João Marcos Costa <joaomarcos.costa@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>