Verify some fields of the USB descriptor to make sure the driver
could be used by the device.

Besides, remove the check of endpoint number in rtl8152_probe().
usb_find_common_endpoints() includes it.

BugLink: https://syzkaller.appspot.com/bug?id=912c9c373656996801b4de61f1e3cb326fe940aa
Reported-by: syzbot+95afd23673f5dd295c57@syzkaller.appspotmail.com
Fixes: c2198943 ("r8152: search the configuration of vendor mode")
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>