Currently, debugfs functions are using symbolic macros as permission
bits, but checkpatch reinforces permission bits in the octal form, as
they are more readable and easier to understand [1]. Moreover, using
the symbolic macro S_IFREG is redundant.

Therefore, use octal permission bits in all debugfs functions.

[1] https://docs.kernel.org/dev-tools/checkpatch.html#permissionsSuggested-by: NJani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: NMaíra Canal <mcanal@igalia.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NMaíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230105193039.287677-1-mcanal@igalia.com