crypto: caam - limit AXI pipeline to a depth of 1

Some i.MX6 devices (imx6D, imx6Q, imx6DL, imx6S, imx6DP and imx6DQ) have
an issue wherein AXI bus transactions may not occur in the correct order.
This isn't a problem running single descriptors, but can be if running
multiple concurrent descriptors. Reworking the CAAM driver to throttle
to single requests is impractical, so this patch limits the AXI pipeline
to a depth of one (from a default of 4) to preclude this situation from
occurring.
This patch applies to known affected platforms.

Signed-off-by: Radu Solea <radu.solea@nxp.com>
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>