Fix two issues to get AMBA widget compile clean under Verilator

The former issue was a Lint warning. HADDR % HSIZE is a modulo operation
of a 32-bit and 3-bit variable. It is cleaner to only use the LSB of
HADDR.

Furthermore, Verilator does not support unpacked arrays in packages.

srdl2sv/components/widgets/srdl2sv_amba3ahblite.sv

@@ -100,7 +100,7 @@ module srdl2sv_amba3ahblite
     logic [31:0] addr_q;
     OP_t         operation_q;
 
-    wire addr_err = (HADDR % HSIZE) != 0;
+    wire addr_err = (HADDR[2:0] % HSIZE) != 3'b0;
 
     always_ff @ (posedge HCLK)
     begin

srdl2sv/components/widgets/srdl2sv_if_pkg.sv

@@ -1,6 +1,6 @@
 package srdl2sv_if_pkg;
 
-typedef struct {
+typedef struct packed { // .Verilator does not support unpacked structs in packages
     logic [31:0] addr;
     logic [31:0] data;
     logic        w_vld;
@@ -8,7 +8,7 @@ typedef struct {
     logic [ 3:0] byte_en;
 } b2r_t;
 
-typedef struct {
+typedef struct packed { // .Verilator does not support unpacked structs in packages
     logic [31:0] data;
     logic        rdy;
     logic        err;