kern: fix dynamic calculation of slab heap size

libraries/libmesosphere/source/init/kern_init_slab_setup.cpp

@@ -127,10 +127,14 @@ namespace ams::kern::init {
             size += util::AlignUp(sizeof(NAME) * (COUNT), alignof(void *)); \
         });
 
-        /* NOTE: This can't be used right now because we don't have all these types implemented. */
-        /* Once we do, uncomment the following and stop using the hardcoded size. */
+        /* Add the size required for each slab. */
         FOREACH_SLAB_TYPE(ADD_SLAB_SIZE)
 
+        #undef ADD_SLAB_SIZE
+
+        /* Add the reserved size. */
+        size += SlabRegionReservedSize;
+
         return size;
     }