wifi: rtw88: Fix memory leak in rtw88_usb

Kmemleak shows the following leak arising from routine in the usb
probe routine:

unreferenced object 0xffff895cb29bba00 (size 512):
  comm "(udev-worker)", pid 534, jiffies 4294903932 (age 102751.088s)
  hex dump (first 32 bytes):
    77 30 30 30 00 00 00 00 02 2f 2d 2b 30 00 00 00  w000...../-+0...
    02 00 2a 28 00 00 00 00 ff 55 ff ff ff 00 00 00  ..*(.....U......
  backtrace:
    [<ffffffff9265fa36>] kmalloc_trace+0x26/0x90
    [<ffffffffc17eec41>] rtw_usb_probe+0x2f1/0x680 [rtw_usb]
    [<ffffffffc03e19fd>] usb_probe_interface+0xdd/0x2e0 [usbcore]
    [<ffffffff92b4f2fe>] really_probe+0x18e/0x3d0
    [<ffffffff92b4f5b8>] __driver_probe_device+0x78/0x160
    [<ffffffff92b4f6bf>] driver_probe_device+0x1f/0x90
    [<ffffffff92b4f8df>] __driver_attach+0xbf/0x1b0
    [<ffffffff92b4d350>] bus_for_each_dev+0x70/0xc0
    [<ffffffff92b4e51e>] bus_add_driver+0x10e/0x210
    [<ffffffff92b50935>] driver_register+0x55/0xf0
    [<ffffffffc03e0708>] usb_register_driver+0x88/0x140 [usbcore]
    [<ffffffff92401153>] do_one_initcall+0x43/0x210
    [<ffffffff9254f42a>] do_init_module+0x4a/0x200
    [<ffffffff92551d1c>] __do_sys_finit_module+0xac/0x120
    [<ffffffff92ee6626>] do_syscall_64+0x56/0x80
    [<ffffffff9300006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

The leak was verified to be real by unloading the driver, which resulted
in a dangling pointer to the allocation.

The allocated memory is freed in rtw_usb_intf_deinit().

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230417160331.23071-1-Larry.Finger@lwfinger.net

drivers/net/wireless/realtek/rtw88/usb.c

@@ -804,6 +804,7 @@ static void rtw_usb_intf_deinit(struct rtw_dev *rtwdev,
 	struct rtw_usb *rtwusb = rtw_get_usb_priv(rtwdev);
 
 	usb_put_dev(rtwusb->udev);
+	kfree(rtwusb->usb_data);
 	usb_set_intfdata(intf, NULL);
 }