[deps] Do not build OpenBLAS Bfloat16 kernels in from source build (#…

…53221)

Not clear why OpenBLAS build fails, GCC 10 should be sufficient to
compile the Bfloat16 kernels and [from what I can
tell](#53172 (comment))
that's the compiler version used in CI, but I don't know how to verify
it since this is a nightly job. If someone who knows more about the
setup can chime in, that'd be great. In the meantime, disabling these
kernels should fix #53172.

deps/openblas.mk

@@ -20,9 +20,6 @@ endif
 # don't touch scheduler affinity since we manage this ourselves
 OPENBLAS_BUILD_OPTS += NO_AFFINITY=1
 
-# Build BFloat16 kernels
-OPENBLAS_BUILD_OPTS += BUILD_BFLOAT16=1
-
 # Build for all architectures - required for distribution
 ifeq ($(SANITIZE_MEMORY),1)
 OPENBLAS_BUILD_OPTS += TARGET=GENERIC