cursor_get_mono_image has been unused since 2018's
0015ca5cba ("ui: remove support for SDL1.2 in favour of SDL2")
Remove it.
Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>