scsi: esas2r: Remove redundant NULL check on buffer

Buffer is a pointer to the static char array event_buffer and therefore
can never be null, so the check is redundant. Remove it.

Detected by CoverityScan, CID#1077556 ("Logically Dead Code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Bradley Grove <bgrove@attotech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/esas2r/esas2r_log.c

@@ -130,11 +130,6 @@ static int esas2r_log_master(const long level,
 
 		spin_lock_irqsave(&event_buffer_lock, flags);
 
-		if (buffer == NULL) {
-			spin_unlock_irqrestore(&event_buffer_lock, flags);
-			return -1;
-		}
-
 		memset(buffer, 0, buflen);
 
 		/*