ASoC: wcd9306: implement analog hpf switch in tx path

The tx path currently has the digital hpf switch to
reduce the pop. Add the analog hpf switch as well to reduce
the turn on tx pop level further.

Change-Id: I2eaaea6b25f8781b9e6f2bc70011bbfd2a7796a2
Signed-off-by: Aravind Kumar <akumark@codeaurora.org>