loader: Changes to use new WSI swapchain extensions.

Use device extension list, not global.  When validating the PhysicalDevice
extensions really need to use the device extension list not the loader's global
list.

Fix include to find aligned_alloc
diff --git a/loader/gpa_helper.h b/loader/gpa_helper.h
index 43432d0..5373603 100644
--- a/loader/gpa_helper.h
+++ b/loader/gpa_helper.h
@@ -23,7 +23,7 @@
  */
 
 #include <string.h>
-#include "wsi_lunarg.h"
+#include "wsi_swapchain.h"
 
 static inline void* globalGetProcAddr(const char *name)
 {
@@ -373,8 +373,6 @@
         return (void*) vkGetDeviceQueue;
     if (!strcmp(name, "CreateCommandBuffer"))
         return (void*) vkCreateCommandBuffer;
-    if (!strcmp(name, "CreateSwapChainWSI"))
-        return (void*) wsi_lunarg_CreateSwapChainWSI;
 
     return NULL;
 }