ASoC: msm8x16-wcd: enable ocp when hph pa is enabled

The present code enables over current protection for
headphones during boot up. This causes leakage current
on the cdc boost rail when the device is in idle state.
The change enables the ocp before hph pa is enabled
and disables them after hph pa is disabled.

CRs-Fixed: 684587
Change-Id: I549dce1b76221f2cf822dac0c819a0a673a3a960
Signed-off-by: Aravind Kumar <akumark@codeaurora.org>