Bluetooth: btrtl: fix out of bounds memory access
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: btrtl: fix out of bounds memory access

The problem is detected by KASAN.
btrtl driver uses private hci data to store 'struct btrealtek_data'.
If btrtl driver is used with btusb, then memory for private hci data
is allocated in btusb. But no private data is allocated after hci_dev,
when btrtl is used with hci_h5.

This commit adds memory allocation for hci_h5 case.

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 BUG: KASAN: slab-out-of-bounds in btrtl_initialize+0x6cc/0x958 [btrtl]
 Write of size 8 at addr ffff00000f5a5748 by task kworker/u9:0/76

 Hardware name: Pine64 PinePhone (1.2) (DT)
 Workqueue: hci0 hci_power_on [bluetooth]
 Call trace:
  dump_backtrace+0x9c/0x128
  show_stack+0x20/0x38
  dump_stack_lvl+0x48/0x60
  print_report+0xf8/0x5d8
  kasan_report+0x90/0xd0
  __asan_store8+0x9c/0xc0
  	 [btrtl]
  h5_btrtl_setup+0xd0/0x2f8 [hci_uart]
  h5_setup+0x50/0x80 [hci_uart]
  hci_uart_setup+0xd4/0x260 [hci_uart]
  hci_dev_open_sync+0x1cc/0xf68 [bluetooth]
  hci_dev_do_open+0x34/0x90 [bluetooth]
  hci_power_on+0xc4/0x3c8 [bluetooth]
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Allocated by task 53:
  kasan_save_stack+0x3c/0x68
  kasan_save_track+0x20/0x40
  kasan_save_alloc_info+0x68/0x78
  __kasan_kmalloc+0xd4/0xd8
  __kmalloc+0x1b4/0x3b0
  hci_alloc_dev_priv+0x28/0xa58 [bluetooth]
  hci_uart_register_device+0x118/0x4f8 [hci_uart]
  h5_serdev_probe+0xf4/0x178 [hci_uart]
  serdev_drv_probe+0x54/0xa0
  really_probe+0x254/0x588
  __driver_probe_device+0xc4/0x210
  driver_probe_device+0x64/0x160
  __driver_attach_async_helper+0x88/0x158
  async_run_entry_fn+0xd0/0x388
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Last potentially related work creation:
  kasan_save_stack+0x3c/0x68
  __kasan_record_aux_stack+0xb0/0x150
  kasan_record_aux_stack_noalloc+0x14/0x20
  __queue_work+0x33c/0x960
  queue_work_on+0x98/0xc0
  hci_recv_frame+0xc8/0x1e8 [bluetooth]
  h5_complete_rx_pkt+0x2c8/0x800 [hci_uart]
  h5_rx_payload+0x98/0xb8 [hci_uart]
  h5_recv+0x158/0x3d8 [hci_uart]
  hci_uart_receive_buf+0xa0/0xe8 [hci_uart]
  ttyport_receive_buf+0xac/0x178
  flush_to_ldisc+0x130/0x2c8
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Second to last potentially related work creation:
  kasan_save_stack+0x3c/0x68
  __kasan_record_aux_stack+0xb0/0x150
  kasan_record_aux_stack_noalloc+0x14/0x20
  __queue_work+0x788/0x960
  queue_work_on+0x98/0xc0
  __hci_cmd_sync_sk+0x23c/0x7a0 [bluetooth]
  __hci_cmd_sync+0x24/0x38 [bluetooth]
  btrtl_initialize+0x760/0x958 [btrtl]
  h5_btrtl_setup+0xd0/0x2f8 [hci_uart]
  h5_setup+0x50/0x80 [hci_uart]
  hci_uart_setup+0xd4/0x260 [hci_uart]
  hci_dev_open_sync+0x1cc/0xf68 [bluetooth]
  hci_dev_do_open+0x34/0x90 [bluetooth]
  hci_power_on+0xc4/0x3c8 [bluetooth]
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20
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