kern: move SecureAppletMemory/KPageBuffer heap into the ResourceRegion

libraries/libmesosphere/include/mesosphere/board/nintendo/nx/kern_k_system_control.hpp

@@ -20,6 +20,9 @@
 namespace ams::kern::board::nintendo::nx {
 
     class KSystemControl : public KSystemControlBase {
+        public:
+            /* This can be overridden as needed. */
+            static constexpr size_t SecureAppletMemorySize = 4_MB;
         public:
             class Init : public KSystemControlBase::Init {
                 public: