crypto: tcrypt - Fix multibuffer skcipher speed test mem leak

[ Upstream commit 1aa33fc8d4032227253ceb736f47c52b859d9683 ]

In the past, the data for mb-skcipher test has been allocated
twice, that means the first allcated memory area is without
free, which may cause a potential memory leakage. So this
patch is to remove one allocation to fix this error.

Fixes: e161c593 ("crypto: tcrypt - add multibuf skcipher...")
Signed-off-by: Zhang Yiqun <zhangyiqun@phytium.com.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>