Fix generation of the subtitling descriptor
Fix generation of the subtitling descriptor

The generation function for the subtitling descriptor erroneously uses the
modulo operation instead of a bitwise AND.

(cherry picked from commit bc7bb320854b0d4bd4f74a5851be0852681d629d)
Signed-off-by: Jean-Paul Saman <c35aa29dc4eb008b34a9adceca7414ea1db124ba@videolan.org>

mwgoldsmith/dvbpsi,mkrufky/libdvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,mwgoldsmith/dvbpsi,mwgoldsmith/dvbpsi,paraeco/libdvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,paraeco/libdvbpsi,mwgoldsmith/dvbpsi