don't kill surfaceflinger when system process dies

Change-Id: I2d3ed87b590f9ccea3fa4af41d92911de070b315
diff --git a/services/surfaceflinger/DisplayHardware/DisplayHardware.cpp b/services/surfaceflinger/DisplayHardware/DisplayHardware.cpp
index a774841..33125c4 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayHardware.cpp
+++ b/services/surfaceflinger/DisplayHardware/DisplayHardware.cpp
@@ -103,6 +103,11 @@
 {
     mNativeWindow = new FramebufferNativeWindow();
     framebuffer_device_t const * fbDev = mNativeWindow->getDevice();
+    if (!fbDev) {
+        LOGE("Display subsystem failed to initialize. check logs. exiting...");
+        exit(0);
+    }
+
     mDpiX = mNativeWindow->xdpi;
     mDpiY = mNativeWindow->ydpi;
     mRefreshRate = fbDev->fps;