libtrellis: Fix bel z-coordinates

Signed-off-by: David Shah <dave@ds0.me>

libtrellis/src/Bels.cpp

diff --git a/libtrellis/src/Bels.cpp b/libtrellis/src/Bels.cpp
index bbcd7d8..d8493a9 100644
--- a/libtrellis/src/Bels.cpp
+++ b/libtrellis/src/Bels.cpp
@@ -261,6 +261,7 @@
     bel.type = graph.ident("EHXPLLL");
     bel.loc.x = x;
     bel.loc.y = y;
+    bel.z = 0;
     auto add_input = [&](const std::string &pin) {
         graph.add_bel_input(bel, graph.ident(pin), x, y, graph.ident(fmt("J" << pin << "_PLL")));
     };
@@ -508,7 +509,7 @@
             add_output("DTROUT" + std::to_string(i));
     } else if (name == "USRMCLK") {
         postfix = "CCLK";
-        bel.z = 0;
+        bel.z = 1;
         add_input("PADDO");
         add_input("PADDT");
         add_output("PADDI");
@@ -634,4 +635,4 @@
 
 
 }
-}
\ No newline at end of file
+}