egl: Remove hash table for displays.

The hash table was used to map a display to a handle.  It is simpler to
cast directly.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>

src/egl/main/eglglobals.c

@@ -13,12 +13,14 @@ static _EGL_DECLARE_MUTEX(_eglGlobalMutex);
 struct _egl_global _eglGlobal =
 {
    &_eglGlobalMutex,       /* Mutex */
+   NULL,                   /* DisplayList */
    1,                      /* FreeScreenHandle */
    0x0,                    /* ClientAPIsMask */
    0,                      /* NumDrivers */
    { NULL },               /* Drivers */
-   1,                      /* NumAtExitCalls */
+   2,                      /* NumAtExitCalls */
    {                       /* AtExitCalls */
+      _eglFiniDisplay,
       _eglUnloadDrivers
    },
 };