crypto: authenc - don't leak pointers to authenc keys

[ Upstream commit ad2fdcdf75d169e7a5aec6c7cb421c0bec8ec711 ]

In crypto_authenc_setkey we save pointers to the authenc keys in
a local variable of type struct crypto_authenc_keys and we don't
zeroize it after use. Fix this and don't leak pointers to the
authenc keys.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>