egl: fix build when using RPi EGL

https://bugzilla.gnome.org/show_bug.cgi?id=795336
diff --git a/gst-libs/gst/gl/egl/gsteglimage.c b/gst-libs/gst/gl/egl/gsteglimage.c
index fdd6038..f12baad 100644
--- a/gst-libs/gst/gl/egl/gsteglimage.c
+++ b/gst-libs/gst/gl/egl/gsteglimage.c
@@ -86,6 +86,10 @@
 #define EGL_DMA_BUF_PLANE0_PITCH_EXT 0x3274
 #endif
 
+#ifdef USE_EGL_RPI
+typedef khronos_uint64_t EGLuint64KHR;
+#endif
+
 GST_DEFINE_MINI_OBJECT_TYPE (GstEGLImage, gst_egl_image);
 
 #ifndef GST_DISABLE_GST_DEBUG