glsl/nir: add pixel_center_integer to shader info

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/shader_info.h

@@ -159,6 +159,8 @@ typedef struct shader_info {
 
          bool post_depth_coverage;
 
+         bool pixel_center_integer;
+
          /** gl_FragDepth layout for ARB_conservative_depth. */
          enum gl_frag_depth_layout depth_layout;
       } fs;