avcodec/pngenc: Remove outer () from macro

The macro is implemented as a do{}while()
enclosing this is () appears to be a GNU extension (6.1 Statements and Declarations in Expressions)
the () is also unneeded and wrong as the macro returns no
value
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/pngenc.c

@@ -232,7 +232,7 @@ static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
     return 0;
 }
 
-#define AV_WB32_PNG(buf, n) (AV_WB32(buf, lrint((n) * 100000)))
+#define AV_WB32_PNG(buf, n) AV_WB32(buf, lrint((n) * 100000))
 static int png_get_chrm(enum AVColorPrimaries prim,  uint8_t *buf)
 {
     double rx, ry, gx, gy, bx, by, wx = 0.3127, wy = 0.3290;