scsi: pm80xx: Add __nonstring annotations for unterminated strings

When a character array without a terminating NUL character has a static
initializer, GCC 15's -Wunterminated-string-initialization will only
warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
with __nonstring to and correctly identify the char array as "not a C
string" and thereby eliminate the warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250310222553.work.437-kees@kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: kees

drivers/scsi/pm8001/pm8001_ctl.c

@@ -644,7 +644,7 @@ static DEVICE_ATTR(gsm_log, S_IRUGO, pm8001_ctl_gsm_log_show, NULL);
 #define FLASH_CMD_SET_NVMD    0x02
 
 struct flash_command {
-     u8      command[8];
+     u8      command[8] __nonstring;
      int     code;
 };