gallium/gallivm: Remove workaround disabling AVX code for newer CPUs
The change enables using full 256-bit AVX and AVX2 instructions
on newer platforms.
Reviewed-by: Alok Hota <alok.hota@intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4225>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4225>