[X86][AVX512] _mm512_stream_load_si512 should take a void const* argument (PR33977)

Based off the Intel Intrinsics guide, we should expect a void const* argument.

Prevents 'passing 'const void *' to parameter of type 'void *' discards qualifiers' warnings.

Differential Revision: https://reviews.llvm.org/D37449

llvm-svn: 312523