CHROMIUM: ALSA: ASoC: max98095 - disable analog inputs to speaker mux.

ChromeOS only ever uses the DAC1 input, and routing the analog inputs
can be harmful (since they are actually DMIC inputs on Lucas).

BUG=chromium-os:37217
TEST=in dev mode run alsamixer and check available Speaker mux inputs.

Change-Id: I77c5b2a829e8c63035ac8006fa8eca722ed50dd0
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/41510
Reviewed-by: Evan Ragsdale <evan.ragsdale@maximintegrated.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
(cherry picked from commit f26950bc5125103403fc3e438c769bc7160e6976)
Reviewed-on: https://gerrit.chromium.org/gerrit/42305