egl: Unhide functionality in _eglInitSurface()

_eglInitResource() was used to memset entire _EGLSurface by
writing more than size of pointed target. This does work
as long as Resource is the first element in _EGLSurface,
this patch fixes such dependency.

Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/egl/main/eglsurface.c

@@ -314,7 +314,9 @@ _eglInitSurface(_EGLSurface *surf, _EGLDisplay *dpy, EGLint type,
       return EGL_FALSE;
    }
 
-   _eglInitResource(&surf->Resource, sizeof(*surf), dpy);
+
+   memset(surf, 0, sizeof(_EGLSurface));
+   _eglInitResource(&surf->Resource, sizeof(_EGLResource), dpy);
    surf->Type = type;
    surf->Config = conf;