arm64/crypto: fix data corruption bug in GHASH algorithm

This fixes a bug in the GHASH algorithm resulting in the calculated hash to be
incorrect if the input is presented in chunks whose size is not a multiple of
16 bytes.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: fdd2389457 ("arm64/crypto: GHASH secure hash using ARMv8 Crypto Extensions")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/crypto/ghash-ce-glue.c

@@ -72,6 +72,7 @@ static int ghash_update(struct shash_desc *desc, const u8 *src,
 				   partial ? ctx->buf : NULL);
 		kernel_neon_end();
 		src += blocks * GHASH_BLOCK_SIZE;
+		partial = 0;
 	}
 	if (len)
 		memcpy(ctx->buf + partial, src, len);