package.bbclass: ensure correct modes on directories

package.bbclass: ensure correct modes on directories

Previously, when we create directories in populate_packages, the
directory modes are not all correct. Take the base-files recipe
as an example. The directory package/home has mode 2755, but
packages-split/base-files/home has mode 0755.

So after using creating directory, we need to use chmod to ensure
it gets the correct mode.

[YOCTO #6517]

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>