Using "pkt->out_len" as the output length of "psa_cipher_[en|de]crypt"
caused a crash in RISCV 64 bits platforms due to misaligned address
access.
The solution is to add a temporary value on the stack to store this lenght
and only after the [en|de]cryption copy it to "pkt->out_len".
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
d76477f9eb