usb-storage: shuttle_usbat: fix initFunction error return

usb-storage: shuttle_usbat: fix initFunction error return

The initFunction is called when probing a new device, its call relation
is like:
USB core: probe() -> usb_stor_probe2() -> usb_stor_acquire_resources()
-> init_usbat_cd() or init_usbat_flash() -> init_usbat()

That is, the error return of the initFunction should tell USB core what
happened instead of using constant or error code like
USB_STOR_TRANSPORT_FAILED.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Link: https://lore.kernel.org/r/20220407022115.3773-1-linma@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>