asoc: tegra: ALC5640 machine: Turn off ext_mic by default

asoc: tegra: ALC5640 machine: Turn off ext_mic by default

Drive ext mic gpio (active low) to 1 during init. It will
be toggled as needed by ext mic events.

Bug 949026

Signed-off-by: Daniel Solomon <daniels@nvidia.com>
(cherry picked from commit de806c193fde5cd8c5b0285efeeaef4adb7be611)
Change-Id: Idd72830d89ebe080739694d7f2c8f6ad80d5cdf5
Reviewed-on: http://git-master/r/93955
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>
Rebase-Id: R97dca78bce264ec489b9bbd7eda137c0bc92b289