GLConsumer: correct EGL_NO_DISPLAY to EGL_NO_CONTEXT

Change-Id: I4dcb57a0db9ee3c5222cd453c9213859384212b0
diff --git a/libs/gui/GLConsumer.cpp b/libs/gui/GLConsumer.cpp
index ccafe81..94e9866 100644
--- a/libs/gui/GLConsumer.cpp
+++ b/libs/gui/GLConsumer.cpp
@@ -505,7 +505,7 @@
         if (mEglDisplay == EGL_NO_DISPLAY) {
             mEglDisplay = dpy;
         }
-        if (mEglContext == EGL_NO_DISPLAY) {
+        if (mEglContext == EGL_NO_CONTEXT) {
             mEglContext = ctx;
         }
     }