fix dot_str_cube not kicking in

when a cube texture is used and dot_str_3d is the texture mode, it is suppose to be flagged by combiner for change to dot_str_cube.

src/core/hle/D3D8/XbPixelShader.cpp

@@ -489,6 +489,10 @@ typedef struct s_CxbxPSDef {
 
 	void AdjustTextureModes(DecodedRegisterCombiner &RC)
 	{
+		if (RC.PSTextureModes[3] = PS_TEXTUREMODES_DOT_STR_CUBE) {
+			RC.TexModeAdjust = true;
+		}
+
 		// if this flag is set, the texture mode for each texture stage is adjusted as follows:
 		if (RC.TexModeAdjust) {
 			for (int i = 0; i < xbox::X_D3DTS_STAGECOUNT; i++) {