bswap: 10L add missing parens around macro args

Originally committed as revision 23070 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/bswap.h

@@ -43,8 +43,8 @@
 #endif
 
 #define AV_BSWAP16C(x) (((x) << 8 & 0xff00)  | ((x) >> 8 & 0x00ff))
-#define AV_BSWAP32C(x) (AV_BSWAP16C(x) << 16 | AV_BSWAP16C(x >> 16))
-#define AV_BSWAP64C(x) (AV_BSWAP32C(x) << 32 | AV_BSWAP32C(x >> 32))
+#define AV_BSWAP32C(x) (AV_BSWAP16C(x) << 16 | AV_BSWAP16C((x) >> 16))
+#define AV_BSWAP64C(x) (AV_BSWAP32C(x) << 32 | AV_BSWAP32C((x) >> 32))
 
 #define AV_BSWAPC(s, x) AV_BSWAP##s##C(x)