ALSA: hda - Add dock support for ThinkPad X250 (17aa:2226)

commit c0278669 upstream.

This model uses the same dock port as the previous generation.

Signed-off-by: Yves-Alexis Perez <corsac@debian.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>