[X86] Use the unaligned vector typedefs for the lddqu intrinsics pointer arguments (PR20670)

Extension to 4390c721 - similar to the vanilla load/store intrinsics, _mm_lddqu_si128/_mm256_lddqu_si256 should take an unaligned pointer, but were using the aligned m128i/m256i types which can cause alignment warnings.

The existing sse3-builtins.c and avx-builtins.c tests in llvm-project\clang\test\CodeGen\X86 should cover this.

Differential Revision: https://reviews.llvm.org/D121815