Improve code readability and checkpatch warnings:

  WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal permissions '0444'.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230415104304.104134-6-krzysztof.kozlowski@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>