slimbus: qcom-ngd-ctrl: Make QMI message rules const

Commit ff6d3658

 ("soc: qcom: qmi: use const for struct
qmi_elem_info") allows QMI message encoding/decoding rules
to be const, so do that for qcom-ngd-ctrl.c.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114403.86230-2-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>