usb: gadget: Fix setting self-powered state on suspend

commit c783e1258f29c5caac9eea0aea6b172870f1baf8 upstream.

cdev->config might be NULL, so check it before dereferencing.

CC: stable <stable@kernel.org>
Fixes: 40e89ff5750f ("usb: gadget: Set self-powered based on MaxPower and bmAttributes")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250220120314.3614330-1-m.szyprowski@samsung.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>