memory: tegra: Prefer octal over symbolic permissions

checkpatch recommends using octal permissions instead of symbolic
permissions. Switch the debugfs files to use the former to silence
these warnings.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230714150116.2823766-1-thierry.reding@gmail.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>