Change the magic values 0, 254 and 255 to END_OF_SEQUENCE, LOAD_PAGE4 and
LOAD_PAGE3 respectively for better source code readability.
Signed-off-by: Marton Nemeth <nm127@freemail.hu>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>