scsi: core: Remove the /proc/scsi/${proc_name} directory earlier

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

scsi: core: Remove the /proc/scsi/${proc_name} directory earlier

Remove the /proc/scsi/${proc_name} directory earlier to fix a race
condition between unloading and reloading kernel modules. This fixes a bug
introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in
the SCSI core").

Fix the following kernel warning:

proc_dir_entry 'scsi/scsi_debug' already registered
WARNING: CPU: 19 PID: 27986 at fs/proc/generic.c:376 proc_register+0x27d/0x2e0
Call Trace:
proc_mkdir+0xb5/0xe0
scsi_proc_hostdir_add+0xb5/0x170
scsi_host_alloc+0x683/0x6c0
sdebug_driver_probe+0x6b/0x2d0 [scsi_debug]
really_probe+0x159/0x540
__driver_probe_device+0xdc/0x230
driver_probe_device+0x4f/0x120
__device_attach_driver+0xef/0x180
bus_for_each_drv+0xe5/0x130
__device_attach+0x127/0x290
device_initial_probe+0x17/0x20
bus_probe_device+0x110/0x130
device_add+0x673/0xc80
device_register+0x1e/0x30
sdebug_add_host_helper+0x1a7/0x3b0 [scsi_debug]
scsi_debug_init+0x64f/0x1000 [scsi_debug]
do_one_initcall+0xd7/0x470
do_init_module+0xe7/0x330
load_module+0x122a/0x12c0
__do_sys_finit_module+0x124/0x1a0
__x64_sys_finit_module+0x46/0x50
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0