Fix invalid calculation of the number of NVOD structures in dr_4b

Since one NVOD reference structure takes 6 bytes, the number of all structures
contained in the descriptor should be the length of its payload divided by 6,
not the remainder of this division.

(cherry picked from commit 057ca087fd1c74a5af92422801ca36f2e23787e0)
Signed-off-by: Jean-Paul Saman <jpsaman@videolan.org>

src/descriptors/dr_4b.c

@@ -65,7 +65,7 @@ dvbpsi_nvod_ref_dr_t* dvbpsi_DecodeNVODReferenceDr(dvbpsi_descriptor_t * p_descr
         return NULL;
 
     /* Decode data */
-    p_decoded->i_references = p_descriptor->i_length % 6;
+    p_decoded->i_references = p_descriptor->i_length / 6;
     if (p_decoded->i_references > 43)
 	p_decoded->i_references = 43;