toolchain/binutils: get rid of outdated libiberty hack

toolchain/binutils: get rid of outdated libiberty hack

This reverts commit 68fcb15f90edd92ef36990c5696b9e79df07a6ec.

binutils syncs libiberty from gcc, which defaults to not installing itself
since [0], see also [1].

That change is apparently part of binutils 2.24, and the oldest supported
version here is 2.37, hence we can remove this hack.

[0] https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=48d7db63ff581b026e057badf39f1f23fdf47928
[1] https://gcc.gnu.org/onlinedocs/libiberty/Using.html

Signed-off-by: Andre Heider <a.heider@gmail.com>