lib/crypto: x86/blake2s: Use vpternlogd for 3-input XORs

lib/crypto: x86/blake2s: Use vpternlogd for 3-input XORs

AVX-512 supports 3-input XORs via the vpternlogd (or vpternlogq)
instruction with immediate 0x96.  This approach, vs. the alternative of
two vpxor instructions, is already used in the CRC, AES-GCM, and AES-XTS
code, since it reduces the instruction count and is faster on some CPUs.
Make blake2s_compress_avx512() take advantage of it too.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251102234209.62133-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>