crypto: simd - correctly take reqsize of wrapped skcipher into account

[ Upstream commit 508a1c4df085a547187eed346f1bfe5e381797f1 ]

The simd wrapper's skcipher request context structure consists
of a single subrequest whose size is taken from the subordinate
skcipher. However, in simd_skcipher_init(), the reqsize that is
retrieved is not from the subordinate skcipher but from the
cryptd request structure, whose size is completely unrelated to
the actual wrapped skcipher.

Reported-by: Qian Cai <cai@gmx.us>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Qian Cai <cai@gmx.us>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>