crypto: x86/sha512-avx2 - add missing vzeroupper

[ Upstream commit 6a24fdfe1edbafacdacd53516654d99068f20eec ]

Since sha512_transform_rorx() uses ymm registers, execute vzeroupper
before returning from it.  This is necessary to avoid reducing the
performance of SSE code.

Fixes: e01d69cb01 ("crypto: sha512 - Optimized SHA512 x86_64 assembly routine using AVX instructions.")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/x86/crypto/sha512-avx2-asm.S

@@ -679,6 +679,7 @@ done_hash:
 	pop	%r12
 	pop	%rbx
 
+	vzeroupper
 	RET
 SYM_FUNC_END(sha512_transform_rorx)