package/gcc: bump 8.x series to version 8.4.0
Remove upstream patch [1].
Rebase and rename 0002-xtensa-fix-PR-target-91880.patch
Tested using gitlab w/ Qemu runtime testing series [2] [3].
[1] https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=
fba5d9b4c0f4488281efbeef56c100bb52e55165
[2] https://gitlab.com/kubu93/buildroot/pipelines/
124684030
[3] http://patchwork.ozlabs.org/project/buildroot/list/?series=159088
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>