wtv: Make WTV_SECTOR_BITS a 64 bit constant

This makes sure that values that are left-shifted by this constant
end up casted to 64 bit before shifting, avoiding overflow if the
value ends up larger than 2 GB.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/wtv.c

@@ -48,7 +48,7 @@
  *
  */
 
-#define WTV_SECTOR_BITS    12
+#define WTV_SECTOR_BITS    INT64_C(12)
 #define WTV_SECTOR_SIZE    (1 << WTV_SECTOR_BITS)
 #define WTV_BIGSECTOR_BITS 18