cifs: Fix warning and UAF when destroy the MR list

In the Linux kernel, the following vulnerability has been resolved:

cifs: Fix warning and UAF when destroy the MR list

If the MR allocate failed, the MR recovery work not initialized
and list not cleared. Then will be warning and UAF when release
the MR:

WARNING: CPU: 4 PID: 824 at kernel/workqueue.c:3066 __flush_work.isra.0+0xf7/0x110
CPU: 4 PID: 824 Comm: mount.cifs Not tainted 6.1.0-rc5+ #82
RIP: 0010:__flush_work.isra.0+0xf7/0x110
Call Trace:
<TASK>
__cancel_work_timer+0x2ba/0x2e0
smbd_destroy+0x4e1/0x990
_smbd_get_connection+0x1cbd/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

BUG: KASAN: use-after-free in smbd_destroy+0x4fc/0x990
Read of size 8 at addr ffff88810b156a08 by task mount.cifs/824
CPU: 4 PID: 824 Comm: mount.cifs Tainted: G W 6.1.0-rc5+ #82
Call Trace:
dump_stack_lvl+0x34/0x44
print_report+0x171/0x472
kasan_report+0xad/0x130
smbd_destroy+0x4fc/0x990
_smbd_get_connection+0x1cbd/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Allocated by task 824:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x7a/0x90
_smbd_get_connection+0x1b6f/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 824:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x143/0x1b0
__kmem_cache_free+0xc8/0x330
_smbd_get_connection+0x1c6a/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Let's initialize the MR recovery work before MR allocate to prevent
the warning, remove the MRs from the list to prevent the UAF.