Refactor SVC handler (#540)

* Refactor SVC handler

* Get rid of KernelErr

* Split kernel code files into multiple folders

Ryujinx.HLE/HOS/Kernel/Memory/KMemoryBlockAllocator.cs

@@ -0,0 +1,19 @@
+namespace Ryujinx.HLE.HOS.Kernel.Memory
+{
+    class KMemoryBlockAllocator
+    {
+        private ulong _capacityElements;
+
+        public int Count { get; set; }
+
+        public KMemoryBlockAllocator(ulong capacityElements)
+        {
+            _capacityElements = capacityElements;
+        }
+
+        public bool CanAllocate(int count)
+        {
+            return (ulong)(Count + count) <= _capacityElements;
+        }
+    }
+}