[syslinux] Spec buffer size 13h v 13

[Bruce Robson]

Whilst looking at the 3.61 isolinux.asm file I noticed that the code
uses a spec buffer size of 13h for the initial BIOS call with the
drive number passed in in DL. It then uses a spec buffer size of 13
when scanning drive numbers from FFh to 81h

Line 291 is
                 mov byte [spec_packet],13h

Lines 576 to 577 are
                 mov si,spec_packet
                 mov byte [si],13                ; Size of buffer

Is the use of 13 an error or is there some reason I don't understand ?