[otbn] Remove unused localparam from otbn_core_model.sv

Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/ip/otbn/dv/model/otbn_core_model.sv b/hw/ip/otbn/dv/model/otbn_core_model.sv
index 527dcba..e73cec1 100644
--- a/hw/ip/otbn/dv/model/otbn_core_model.sv
+++ b/hw/ip/otbn/dv/model/otbn_core_model.sv
@@ -28,8 +28,7 @@
   // real implementation running alongside and we check DMEM contents on completion.
   parameter string DesignScope = "",
 
-  localparam int ImemAddrWidth = prim_util_pkg::vbits(ImemSizeByte),
-  localparam int DmemAddrWidth = prim_util_pkg::vbits(DmemSizeByte)
+  localparam int ImemAddrWidth = prim_util_pkg::vbits(ImemSizeByte)
 )(
   input  logic  clk_i,
   input  logic  rst_ni,