Revert "libvpx.recipe: Use only -O1 with llvm/clang"
Revert "libvpx.recipe: Use only -O1 with llvm/clang"

This reverts commit 86df1d951783aad7c83ff6cece1020cc6a712069. Fixes in
git after v.1.3.0 should render forcing -O1 unnecessary.

jackjansen/cerbero,EricssonResearch/cerbero,shoreflyer/cerbero,sdroege/cerbero,nirbheek/cerbero,multipath-rtp/cerbero,flexVDI/cerbero,EricssonResearch/cerbero,justinjoy/cerbero,EricssonResearch/cerbero,AlertMe/cerbero,sdroege/cerbero,ford-prefect/cerbero,ikonst/cerbero,fluendo/cerbero,atsushieno/cerbero,fluendo/cerbero,sdroege/cerbero,ikonst/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,justinjoy/cerbero,ford-prefect/cerbero,fluendo/cerbero,justinjoy/cerbero,centricular/cerbero,atsushieno/cerbero,GStreamer/cerbero,ford-prefect/cerbero,ramaxlo/cerbero,OptoFidelity/cerbero,GStreamer/cerbero,jackjansen/cerbero,AlertMe/cerbero,shoreflyer/cerbero,atsushieno/cerbero,ramaxlo/cerbero,EricssonResearch/cerbero,OptoFidelity/cerbero,flexVDI/cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,GStreamer/cerbero,multipath-rtp/cerbero,shoreflyer/cerbero,nirbheek/cerbero,nirbheek/cerbero-old,EricssonResearch/cerbero,ramaxlo/cerbero,nirbheek/cerbero-old,freedesktop-unofficial-mirror/gstreamer__cerbero,ford-prefect/cerbero,nirbheek/cerbero,OptoFidelity/cerbero,nirbheek/cerbero-old,AlertMe/cerbero,OptoFidelity/cerbero,centricular/cerbero,multipath-rtp/cerbero,flexVDI/cerbero,jackjansen/cerbero,atsushieno/cerbero,nzjrs/cerbero,sdroege/cerbero,superdump/cerbero,nzjrs/cerbero,justinjoy/cerbero,ramaxlo/cerbero,atsushieno/cerbero,fluendo/cerbero,lubosz/cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,multipath-rtp/cerbero,centricular/cerbero,ikonst/cerbero,lubosz/cerbero,lubosz/cerbero,shoreflyer/cerbero,sdroege/cerbero,nzjrs/cerbero,jackjansen/cerbero,ramaxlo/cerbero,GStreamer/cerbero,nirbheek/cerbero-old,flexVDI/cerbero,nzjrs/cerbero,ikonst/cerbero,superdump/cerbero,flexVDI/cerbero,fluendo/cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,superdump/cerbero,superdump/cerbero,nirbheek/cerbero,lubosz/cerbero,shoreflyer/cerbero,multipath-rtp/cerbero,centricular/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,AlertMe/cerbero,AlertMe/cerbero,centricular/cerbero,nzjrs/cerbero,ikonst/cerbero,GStreamer/cerbero