Pick commit 24a4f14 from Linux
upstream.

    crypto: caam - constify pointer to descriptor buffer

    The pointer to the descriptor buffer is not touched,
    it always points to start of the descriptor buffer.
    Thus, make it const.

    Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>