Revert "GL: fixed irregular sized v210 display"

since previous commit, it should not be needed

It seems now the problem (solved by the previous commit) was possibly
caused by different rounding modes of int() cast (Windows having
FE_UPWARD?).

This reverts commit c2437894fa.

src/video_display/gl.cpp

@@ -196,7 +196,7 @@ void main(void) {
 
   // interpolate (0,1) texcoords to [0,719]
   int texcoordDenormX;
-  texcoordDenormX = int(round(gl_TexCoord[0].x * imageWidth - .4999));
+  texcoordDenormX = int(round(gl_TexCoord[0].x * imageWidth - .5));
 
   // 0 1 1 2 3 3 4 5 5 6 7 7 etc.
   int yOffset;