Replace symbolic permission macros with octal permission numbers
because octal permission numbers are easier to read and understand
instead of their symbolic macro names.

No functional change.
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Utkarsh Verma <utkarshverma294@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>