CHROMIUM: ALSA: ASoC: Get snow hp/mic detect GPIOs from device tree.

CHROMIUM: ALSA: ASoC: Get snow hp/mic detect GPIOs from device tree.

Get the GPIOs used for hp and mic detect from the device tree.  Getting
them from device tree allows for the pull up/pull down to be properly
configured (it is disabled) and for mic detect to be inverted.

BUG=chrome-os-partner:10849
TEST=aplay/arecord on snow work.  evtest shows events for hp and mic
detection.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Change-Id: I93d994a2ec5c22683c6eb5fd502f6a54c8e8d964
Reviewed-on: https://gerrit.chromium.org/gerrit/29626
Reviewed-by: Olof Johansson <olofj@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Ready: Dylan Reid <dgreid@chromium.org>