fix: replace UNUSEDPARAM/UNUSEDSIGNAL with UNUSED for verilator lint

Verilator does not recognize UNUSEDPARAM or UNUSEDSIGNAL.
Correct suppression code is UNUSED.

rtl/ip/mlkem/sha3/sha3_top.v

@@ -123,10 +123,10 @@ module sha3_top (
     // Keccak core
     // ================================================================
     wire              kc_valid_i;
-    /* verilator lint_off UNUSEDSIGNAL */
+    /* verilator lint_off UNUSED */
     wire [1599:0]     kc_state_o;
     wire              kc_ready_o;
-    /* verilator lint_on UNUSEDSIGNAL */
+    /* verilator lint_on UNUSED */
     wire              kc_valid_o;
 
     // Keccak input: multi-block xored state when mb_en, else single-block absorb.

rtl/ip/mlkem/sha3/sha3_top_shared.v

@@ -42,9 +42,9 @@ module sha3_top_shared (
     // --- external (shared) keccak_core interface ---
     input  [1599:0]    kc_state_o,
     input              kc_valid_o,
-    /* verilator lint_off UNUSEDSIGNAL */
+    /* verilator lint_off UNUSED */
     input              kc_ready_o,
-    /* verilator lint_on UNUSEDSIGNAL */
+    /* verilator lint_on UNUSED */
     output [1599:0]    kc_state_i,
     output             kc_valid_i,
     output             kc_ready_i