[smc/hw] Save target PC during IRQ after iPTW

-If an IRQ arrives in the middle of a boundary iPTW and is serviced
after iPTW completion, ensure the target PC is saved if the IRQ requires
another iPTW

Bug: 296913208

Change-Id: I47431ba0a65db3f115bb2b84811b1bed004f0d4f

hw/top_matcha/ip/smc/rtl/smc_controller.sv

diff --git a/hw/top_matcha/ip/smc/rtl/smc_controller.sv b/hw/top_matcha/ip/smc/rtl/smc_controller.sv
index fc4f76d..275ec8c 100644
--- a/hw/top_matcha/ip/smc/rtl/smc_controller.sv
+++ b/hw/top_matcha/ip/smc/rtl/smc_controller.sv
@@ -762,11 +762,11 @@
             exc_cause_o = ExcCauseIrqTimerS;
           end
 
-          if (ptw_spec_walk_i) begin
+          if (ptw_spec_walk_i | ptw_instr_walk_i) begin
             ptw_pc_change_instr_d = 1'b1;
-            ctrl_fsm_ns = PAGING_IF;
             ptw_exc_cause_d = exc_cause_o;
             ptw_exc_pc_mux_d = exc_pc_mux_o;
+            ptw_pc_mux_d = pc_mux_o;
           end
 
         end