bsps/shared/*: Address unused parameter warnings

Add "(void) param;" annotation to address unused parameter warnings.
Found with GCC's warning -Wunused-parameter.

bsps/shared/start/bspfatal-default.c

@@ -50,6 +50,8 @@ void bsp_fatal_extension(
   rtems_fatal_code code
 )
 {
+  (void) always_set_to_false;
+
   #if defined(RTEMS_SMP)
     if (
       source == RTEMS_FATAL_SOURCE_SMP &&

bsps/shared/start/sbrk.c

@@ -42,6 +42,8 @@
 
 void * sbrk(ptrdiff_t incr)
 {
+  (void) incr;
+
   errno = ENOMEM;
   return (void *)-1;
 }

bsps/shared/start/stackalloc.c

@@ -45,6 +45,8 @@ static Heap_Control bsp_stack_heap;
 
 void bsp_stack_allocate_init(size_t stack_space_size)
 {
+  (void) stack_space_size;
+
   _Heap_Initialize(
     &bsp_stack_heap,
     bsp_section_stack_begin,