atm: idt77252: fix kmemleak when rmmod idt77252

atm: idt77252: fix kmemleak when rmmod idt77252

There are memory leaks reported by kmemleak:

  unreferenced object 0xffff888106500800 (size 128):
    comm "modprobe", pid 1017, jiffies 4297787785 (age 67.152s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<00000000970ce626>] __kmem_cache_alloc_node+0x20c/0x380
      [<00000000fb5f78d9>] kmalloc_trace+0x2f/0xb0
      [<000000000e947e2a>] idt77252_init_one+0x2847/0x3c90 [idt77252]
      [<000000006efb048e>] local_pci_probe+0xeb/0x1a0
    ...

  unreferenced object 0xffff888106500b00 (size 128):
    comm "modprobe", pid 1017, jiffies 4297787785 (age 67.152s)
    hex dump (first 32 bytes):
      00 20 3d 01 80 88 ff ff 00 20 3d 01 80 88 ff ff  . =...... =.....
      f0 23 3d 01 80 88 ff ff 00 20 3d 01 00 00 00 00  .#=...... =.....
    backtrace:
      [<00000000970ce626>] __kmem_cache_alloc_node+0x20c/0x380
      [<00000000fb5f78d9>] kmalloc_trace+0x2f/0xb0
      [<00000000f451c5be>] alloc_scq.constprop.0+0x4a/0x400 [idt77252]
      [<00000000e6313849>] idt77252_init_one+0x28cf/0x3c90 [idt77252]

The root cause is traced to the vc_maps which alloced in open_card_oam()
are not freed in close_card_oam(). The vc_maps are used to record
open connections, so when close a vc_map in close_card_oam(), the memory
should be freed. Moreover, the ubr0 is not closed when close a idt77252
device, leading to the memory leak of vc_map and scq_info.

Fix them by adding kfree in close_card_oam() and implementing new
close_card_ubr0() to close ubr0.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Francois Romieu <romieu@fr.zoreil.com>
Link: https://lore.kernel.org/r/20230320143318.2644630-1-lizetao1@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>