scsi_debug: test always evaluates to false, || should be used instead

cppcheck found the following issue:
(warning) Logical conjunction always evaluates to false:
  alloc_len < 4 && alloc_len > 65535.

..the test should be instead:

  if (alloc_len < 4 || alloc_len > 65536)

This error was introduced by recent commit 38d5c833
("scsi_debug: add Report supported opcodes+tmfs; Compare and write")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/scsi_debug.c

@@ -1623,7 +1623,7 @@ resp_rsup_opcodes(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 	req_opcode = cmd[3];
 	req_sa = get_unaligned_be16(cmd + 4);
 	alloc_len = get_unaligned_be32(cmd + 6);
-	if (alloc_len < 4 && alloc_len > 0xffff) {
+	if (alloc_len < 4 || alloc_len > 0xffff) {
 		mk_sense_invalid_fld(scp, SDEB_IN_CDB, 6, -1);
 		return check_condition_result;
 	}