fpga: dfl-fme: constify pointers to hwmon_channel_info

Statically allocated array of pointers to hwmon_channel_info can be made
const for safety.

Reviewed-by: Russ Weight <russell.h.weight@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20230511175449.282069-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Xu Yilun <yilun.xu@intel.com>