ASoC: wcd9320: enable headphone over current protection

Unlike prior CODEC, headphone OCP detection is not enabled
by default in CODEC hardware. Update CODEC driver to enable
detection functionality.

Change-Id: I54fb97debb97dd23ab42f26f0f8aa0a1121c6ccf
Signed-off-by: Patrick Lai <plai@codeaurora.org>