memory: tegra: Constify struct thermal_cooling_device_ops

memory: tegra: Constify struct thermal_cooling_device_ops

The only usage of tegra210_emc_cd_ops is to pass its address to
devm_thermal_of_cooling_device_register() which is a pointer to const
struct thermal_cooling_device_ops. Make it const to allow the compiler
to put it in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20211128204158.19544-1-rikard.falkeborn@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>