Add --print-fps to enable FPS counter on start

The FPS counter could be enabled/disabled via MOD+i.

Add a command line option to enable it on start. This is consistent with
other features like --turn-screen-off or --fullscreen.

Fixes #468 <https://github.com/Genymobile/scrcpy/issues/468>
PR #3030 <https://github.com/Genymobile/scrcpy/pull/3030>

app/src/scrcpy.c

@@ -588,6 +588,7 @@ aoa_hid_end:
             .rotation = options->rotation,
             .mipmaps = options->mipmaps,
             .fullscreen = options->fullscreen,
+            .start_fps_counter = options->start_fps_counter,
             .buffering_time = options->display_buffer,
         };