[rend2] Fix korriban shaders with multiply blend stages

Stages that are used to get some more detail shouldnt be collapsed with lighting because it will multiply lighting again and again which leads to incorrect darkening

shared/rd-rend2/tr_shader.cpp

@@ -3372,6 +3372,14 @@ static qboolean CollapseStagesToGLSL(void)
 			if (pStage->bundle[0].tcGen >= TCGEN_LIGHTMAP && pStage->bundle[0].tcGen <= TCGEN_LIGHTMAP3)
 				continue;
 
+			if (i > 0)
+			{
+				int blendBits = pStage->stateBits & (GLS_DSTBLEND_BITS | GLS_SRCBLEND_BITS);
+				if (blendBits == (GLS_DSTBLEND_SRC_COLOR | GLS_SRCBLEND_ZERO) ||
+					blendBits == (GLS_DSTBLEND_ZERO | GLS_SRCBLEND_DST_COLOR))
+					continue;
+			}
+
 			diffuse  = pStage;
 			parallax = qfalse;
 			lightmap = NULL;