Remove qemu_console_displaystate(), qemu_remove_kbd_event_handler(),
qemu_different_endianness_pixelformat() and cpkey(), since they are
completely unused.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>