[aes] Fix AscentLint errors Signed-off-by: Pirmin Vogel <vogelpi@lowrisc.org>

diff --git a/hw/ip/aes/lint/aes.waiver b/hw/ip/aes/lint/aes.waiver
index 6186704..52820b5 100644
--- a/hw/ip/aes/lint/aes.waiver
+++ b/hw/ip/aes/lint/aes.waiver

@@ -68,6 +68,3 @@
 
 waive -rules {ONE_BRANCH} -location {aes_sel_buf_chk.sv} -regexp {unique case statement has only one branch} \
       -comment "check for legal combinations only, assert error signal otherwise"
-
-waive -rules {MIXED_SIGN} -location {aes_control_fsm.sv} -regexp {Signed operand '(prng_reseed_rate_i == PER_1 ? BlockCtrWidth'(0) : prng_reseed_rate_i == PER_64 ? BlockCtrWidth'(63) : prng_reseed_rate_i == PER_8K ? BlockCtrWidth'(8191) : BlockCtrWidth'(0))' and unsigned operand 'block_ctr_decr ? gen_block_ctr.block_ctr_q - BlockCtrWidth'(1) : gen_block_ctr.block_ctr_q' encountered in a conditional expression} \
-      -comment "In line with our style guide, BlockCtrWidth'(x) results in a signed operand"

diff --git a/hw/ip/aes/rtl/aes_control_fsm.sv b/hw/ip/aes/rtl/aes_control_fsm.sv
index fefae18..7758f06 100644
--- a/hw/ip/aes/rtl/aes_control_fsm.sv
+++ b/hw/ip/aes/rtl/aes_control_fsm.sv

@@ -833,16 +833,19 @@
   if (Masking) begin : gen_block_ctr
     logic                     block_ctr_set;
     logic [BlockCtrWidth-1:0] block_ctr_d, block_ctr_q;
+    logic [BlockCtrWidth-1:0] block_ctr_set_val, block_ctr_decr_val;
 
     assign block_ctr_expr = block_ctr_q == '0;
     assign block_ctr_set  = ctrl_we_q | (block_ctr_decr & (block_ctr_expr | cipher_prng_reseed_i));
 
-    assign block_ctr_d =
-        block_ctr_set  ?
-            (prng_reseed_rate_i == PER_1  ? BlockCtrWidth'(0)    :
-             prng_reseed_rate_i == PER_64 ? BlockCtrWidth'(63)   :
-             prng_reseed_rate_i == PER_8K ? BlockCtrWidth'(8191) : BlockCtrWidth'(0)) :
-        block_ctr_decr ? block_ctr_q - BlockCtrWidth'(1) : block_ctr_q;
+    assign block_ctr_set_val  = prng_reseed_rate_i == PER_1  ? '0                   :
+                                prng_reseed_rate_i == PER_64 ? BlockCtrWidth'(63)   :
+                                prng_reseed_rate_i == PER_8K ? BlockCtrWidth'(8191) : '0;
+
+    assign block_ctr_decr_val = block_ctr_q - BlockCtrWidth'(1);
+
+    assign block_ctr_d = block_ctr_set  ? block_ctr_set_val  :
+                         block_ctr_decr ? block_ctr_decr_val : block_ctr_q;
 
     always_ff @(posedge clk_i or negedge rst_ni) begin : reg_block_ctr
       if (!rst_ni) begin

diff --git a/hw/ip/aes/rtl/aes_core.sv b/hw/ip/aes/rtl/aes_core.sv
index bc35076..04771b3 100644
--- a/hw/ip/aes/rtl/aes_core.sv
+++ b/hw/ip/aes/rtl/aes_core.sv

@@ -927,6 +927,10 @@
   logic unused_alert_signals;
   assign unused_alert_signals = ^reg2hw.alert_test;
 
+  // Unused inputs
+  logic unused_idle;
+  assign unused_idle = reg2hw.status.idle.q;
+
   ////////////////
   // Assertions //
   ////////////////