usb: musb: fix gadget state on disconnect

usb: musb: fix gadget state on disconnect

commit 67a59f82196c8c4f50c83329f0577acfb1349b50 upstream.

When unplugging the USB cable or disconnecting a gadget in usb peripheral mode with
echo "" > /sys/kernel/config/usb_gadget/<your_gadget>/UDC,
/sys/class/udc/musb-hdrc.0/state does not change from USB_STATE_CONFIGURED.

Testing on dwc2/3 shows they both update the state to USB_STATE_NOTATTACHED.

Add calls to usb_gadget_set_state in musb_g_disconnect and musb_gadget_stop
to fix both cases.

Fixes: 49401f4169c0 ("usb: gadget: introduce gadget state tracking")
Cc: stable@vger.kernel.org
Co-authored-by: Yehowshua Immanuel <yehowshua.immanuel@twosixtech.com>
Signed-off-by: Yehowshua Immanuel <yehowshua.immanuel@twosixtech.com>
Signed-off-by: Drew Hamilton <drew.hamilton@zetier.com>
Link: https://lore.kernel.org/r/20250701154126.8543-1-drew.hamilton@zetier.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>