openblas: turn off AVX512 optimizations
The AVX512 optimization has a bug in openblas-0.3.5
and can also lead to slower code on Xeon Silver CPUs.
See https://github.com/xianyi/OpenBLAS/issues/1955
and https://github.com/xianyi/OpenBLAS/issues/2029
(cherry picked from commit 7035aa7de4fa8668b6d7feab7b1ed58015689d09)