scsi: target: Remove unused list 'device_list'

Commit be50f538 ("target: remove g_device_list") made 'g_device_list'
local as 'device_list' but also removed the last use of it, the code that
added the device to it.

Build tested only.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20240503234419.171823-1-linux@treblig.orgSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_device.c

@@ -37,7 +37,6 @@
 #include "target_core_ua.h"
 
 static DEFINE_MUTEX(device_mutex);
-static LIST_HEAD(device_list);
 static DEFINE_IDR(devices_idr);
 
 static struct se_hba *lun0_hba;