desc_48: fix make check

dvb/si/desc_48.h

@@ -75,7 +75,7 @@ static inline void desc48_set_provider(uint8_t *p_desc,
 static inline uint8_t *desc48_get_provider(const uint8_t *p_desc,
                                                  uint8_t *pi_length)
 {
-    uint8_t *p = p_desc + DESC48_HEADER_SIZE;
+    uint8_t *p = (uint8_t *)p_desc + DESC48_HEADER_SIZE;
     *pi_length = p[0];
     return p + 1;
 }