doc: release-notes-2.5: add release notes for USB
doc: release-notes-2.5: add release notes for USB

Add release notes for USB.

Signed-off-by: Johann Fischer <64a5f06fca6b2d93d742efe564789153170f6198@nordicsemi.no>

nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr