tegra: Include private.h in list of source files

This makes sure that the proper dependencies are created and that the
file is distributed.

Signed-off-by: Thierry Reding <treding@nvidia.com>

tegra/meson.build

@@ -20,7 +20,12 @@
 
 libdrm_tegra = library(
   'drm_tegra',
-  [files('tegra.c'), config_file],
+  [
+    files(
+      'private.h', 'tegra.c'
+    ),
+    config_file
+  ],
   include_directories : [inc_root, inc_drm],
   link_with : libdrm,
   dependencies : [dep_pthread_stubs, dep_atomic_ops],