Revert "package/binutils: install libiberty for host build"

Revert "package/binutils: install libiberty for host build"

This reverts commit 7ec7ba54055919d89afc93606794d161505fa2d8, as it
causes build failures of host-gdb:

/usr/bin/ld: /home/buildroot/autobuild/instance-0/output/host/lib/libiberty.a(cplus-dem.o): relocation R_X86_64_PC32 against symbol `_sch_istable' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value

Indeed, the host-gdb build picks up the libiberty installed in
$(HOST_DIR) instead of using its own internal version. This needs to
be addressed before we can make host-binutils install libiberty in
$(HOST_DIR).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>