staging/olpc: lock_fb_info can't fail

Simply because olpc never unregisters the damn thing. It also
registers the framebuffer directly by poking around in fbdev
core internals, so it's all around rather broken.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jens Frederich <jfrederich@gmail.com>
Cc: Daniel Drake <dsd@laptop.org>
Cc: Jon Nettleton <jon.nettleton@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-15-daniel.vetter@ffwll.ch