usb: gadget: legacy: fix error return code in gfs_bind

We must return negative error code -ENOMEM if function
'usb_otg_descriptor_alloc()' fails.

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Link: https://lore.kernel.org/r/20230621124323.47183-1-harperchen1110@gmail.com


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