ASoC: omap: Amstrad E3 needs TTY support for codec

The cx20442 codec driver used here requires the TTY layer to
be enabled, or we get a link error:

sound/built-in.o: In function `cx20442_codec_remove':
cx20442.c:398: undefined reference to `tty_hangup'
sound/built-in.o: In function `ams_delta_remove':
ams-delta.c:613: undefined reference to `tty_unregister_ldisc'
sound/built-in.o: In function `ams_delta_cx20442_init':
ams-delta.c:559: undefined reference to `tty_register_ldisc'

This adds the missing dependency in the E3 configuration, there
was already one for the codec.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xia Kaixu <kaixu.xia@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>