mISDN: hfcpci: Fix warning when deleting uninitialized timer

mISDN: hfcpci: Fix warning when deleting uninitialized timer

With CONFIG_DEBUG_OBJECTS_TIMERS unloading hfcpci module leads
to the following splat:

[  250.215892] ODEBUG: assert_init not available (active state 0) object: ffffffffc01a3dc0 object type: timer_list hint: 0x0
[  250.217520] WARNING: CPU: 0 PID: 233 at lib/debugobjects.c:612 debug_print_object+0x1b6/0x2c0
[  250.218775] Modules linked in: hfcpci(-) mISDN_core
[  250.219537] CPU: 0 UID: 0 PID: 233 Comm: rmmod Not tainted 6.17.0-rc2-g6f713187ac98 #2 PREEMPT(voluntary)
[  250.220940] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[  250.222377] RIP: 0010:debug_print_object+0x1b6/0x2c0
[  250.223131] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 41 56 48 8b 14 dd a0 4e 01 9f 48 89 ee 48 c7 c7 20 46 01 9f e8 cb 84d
[  250.225805] RSP: 0018:ffff888015ea7c08 EFLAGS: 00010286
[  250.226608] RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff9be93a95
[  250.227708] RDX: 1ffff1100d945138 RSI: 0000000000000008 RDI: ffff88806ca289c0
[  250.228993] RBP: ffffffff9f014a00 R08: 0000000000000001 R09: ffffed1002bd4f39
[  250.230043] R10: ffff888015ea79cf R11: 0000000000000001 R12: 0000000000000001
[  250.231185] R13: ffffffff9eea0520 R14: 0000000000000000 R15: ffff888015ea7cc8
[  250.232454] FS:  00007f3208f01540(0000) GS:ffff8880caf5a000(0000) knlGS:0000000000000000
[  250.233851] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  250.234856] CR2: 00007f32090a7421 CR3: 0000000004d63000 CR4: 00000000000006f0
[  250.236117] Call Trace:
[  250.236599]  <TASK>
[  250.236967]  ? trace_irq_enable.constprop.0+0xd4/0x130
[  250.237920]  debug_object_assert_init+0x1f6/0x310
[  250.238762]  ? __pfx_debug_object_assert_init+0x10/0x10
[  250.239658]  ? __lock_acquire+0xdea/0x1c70
[  250.240369]  __try_to_del_timer_sync+0x69/0x140
[  250.241172]  ? __pfx___try_to_del_timer_sync+0x10/0x10
[  250.242058]  ? __timer_delete_sync+0xc6/0x120
[  250.242842]  ? lock_acquire+0x30/0x80
[  250.243474]  ? __timer_delete_sync+0xc6/0x120
[  250.244262]  __timer_delete_sync+0x98/0x120
[  250.245015]  HFC_cleanup+0x10/0x20 [hfcpci]
[  250.245704]  __do_sys_delete_module+0x348/0x510
[  250.246461]  ? __pfx___do_sys_delete_module+0x10/0x10
[  250.247338]  do_syscall_64+0xc1/0x360
[  250.247924]  entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fix this by initializing hfc_tl timer with DEFINE_TIMER macro.
Also, use mod_timer instead of manual timeout update.

Fixes: 87c5fa1bb426 ("mISDN: Add different different timer settings for hfc-pci")
Fixes: 175302f6b79e ("mISDN: hfcpci: Fix use-after-free bug in hfcpci_softirq")
Signed-off-by: Vladimir Riabchun <ferr.lambarginio@gmail.com>
Link: https://patch.msgid.link/aKiy2D_LiWpQ5kXq@vova-pc
Signed-off-by: Jakub Kicinski <kuba@kernel.org>