Added 8259 PIC support

xtoskrnl/hl/amd64/ioport.c

@@ -143,3 +143,19 @@ HlIoPortOutShort(IN USHORT Port,
                  : "a" (Value),
                    "Nd" (Port));
 }
+
+/**
+ * Sends a 0x00 byte to an unused IO port.
+ * This operation takes 1 - 4 microseconds and functions as an
+ * imprecise wait function.
+ * 
+ * @return This routine does not return any value.
+ * 
+ * @since XT 1.0
+ */
+XTCDECL
+VOID
+HlIoPortWait(VOID)
+{
+    HlIoPortOutByte(0x80, 0x00);
+}