Added tri-state buffer mapping file

sky130/openlane/sky130_fd_sc_hd/tribuff_map.v

diff --git a/sky130/openlane/sky130_fd_sc_hd/tribuff_map.v b/sky130/openlane/sky130_fd_sc_hd/tribuff_map.v
new file mode 100644
index 0000000..0bbfd9f
--- /dev/null
+++ b/sky130/openlane/sky130_fd_sc_hd/tribuff_map.v
@@ -0,0 +1,6 @@
+module \$_TBUF_ (input A, input E, output Y);
+  sky130_fd_sc_hd__ebufn_2 _TECHMAP_REPLACE_ (
+    .A(A),
+    .Z(Z),
+    .TE_B(~E));
+endmodule
\ No newline at end of file