Move include paths and add new target_include_directories to support
backwards compatibility:
* /include -> /include/zephyr
example: <irq.h> -> <zephyr/irq.h>
Issue #41543
Signed-off-by: Yuval Peress <peress@google.com>
Until now the whole USB device stack code is located
in the top subsys/usb directory. Move it to own directory
in preparation for upcoming extension and rework of USB support.
Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>