src/dvbpsi.h: set i_last_section_number when adding a new section to the end of the list

The function dvbpsi_decoder_psi_section_add() never set p_decoder::i_last_section_number when
adding a new section at the end of the list. This was left to the decoder implementations. However
the correct action would have been to set p_decoder::i_last_section_number in dvbpsi_decoder_psi_section_add().

(cherry picked from commit 7e9f4ed3)

src/dvbpsi.c

@@ -211,6 +211,7 @@ bool dvbpsi_decoder_psi_section_add(dvbpsi_decoder_t *p_decoder, dvbpsi_psi_sect
     /* Add to end of list */
     if (p_prev->i_number < p_section->i_number)
     {
+        p_decoder->i_last_section_number = p_section->i_number;
         p_prev->p_next = p_section;
         p_section->p_next = NULL;
     }