dt-bindings: remoteproc: imx_rproc: support i.MX8MN/P

Add i.MX8MN/P remote processor(Cortex-M7) compatible string

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1620274123-1461-4-git-send-email-peng.fan@oss.nxp.com


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>