usb: move CONFIG_USB_HUB_DEBOUNCE_TIMEOUT to USB

This configuration setting is only relevant if the board supports USB.
It should not be in the main menu but in the USB menu.

The setting is only relevant in USB host mode.

Fixes: 5454dea3 ("usb: hub: allow to increase HUB_DEBOUNCE_TIMEOUT")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>