Skip bounding box when set to 0.

VectorTD does this, for example, and it seems innocent, just resetting all
cmds.  Not sure what it should set the flag to, though.

GPU/GLES/GLES_GPU.cpp

@@ -824,6 +824,12 @@ void GLES_GPU::ExecuteOp(u32 op, u32 diff) {
 		break;
 
 	case GE_CMD_BOUNDINGBOX:
+		// Just resetting, nothing to bound.
+		if (data == 0) {
+			// TODO: Should this set the bboxResult?  Let's set it true for now.
+			currentList->bboxResult = true;
+			break;
+		}
 		if ((data % 8 == 0) && data < 64) {  // Sanity check
 			void *control_points = Memory::GetPointer(gstate_c.vertexAddr);
 			if (gstate.vertType & GE_VTYPE_IDX_MASK) {