egl: fix tracking of priv features in check_egl_extensions

check_egl_extensions was mistakenly always ORing in the priv flags of
the first feature_data entry instead of referencing the i variable to
index into the array of feature data after determining that an extension
is available.

Signed-off-by: Neil Roberts <neil@linux.intel.com>

cogl/winsys/cogl-winsys-egl.c

@@ -358,7 +358,7 @@ check_egl_extensions (CoglRenderer *renderer)
                              egl_renderer))
       {
         egl_renderer->private_features |=
-          winsys_feature_data[0].feature_flags_private;
+          winsys_feature_data[i].feature_flags_private;
       }
 }