Corrected some things from the initial pass of removing unused GPIO
signals and analog signals, and converting from EFS8A to sky130A.
Close to being able to simulate, with some hand-editing of the
standard cell library files.
diff --git a/verilog/rtl/ring_osc2x13.v b/verilog/rtl/ring_osc2x13.v
index 4363c00..c0531bd 100644
--- a/verilog/rtl/ring_osc2x13.v
+++ b/verilog/rtl/ring_osc2x13.v
@@ -28,7 +28,7 @@
 
     sky130_fd_sc_hd__einvn_4 delayenb1 (
 	.A(ts),
-	.TEB(trim[1]),
+	.TE_B(trim[1]),
 	.Z(d1)
     );
 
@@ -45,7 +45,7 @@
 
     sky130_fd_sc_hd__einvn_8 delayenb0 (
 	.A(ts),
-	.TEB(trim[0]),
+	.TE_B(trim[0]),
 	.Z(out)
     );
 
@@ -72,7 +72,7 @@
 
     sky130_fd_sc_hd__einvn_4 delayenb1 (
 	.A(in),
-	.TEB(trim[1]),
+	.TE_B(trim[1]),
 	.Z(d1)
     );
 
@@ -89,7 +89,7 @@
 
     sky130_fd_sc_hd__einvn_8 delayenb0 (
 	.A(in),
-	.TEB(ctrl0),
+	.TE_B(ctrl0),
 	.Z(out)
     );