ASoC: wcd: handle headset related pinctrl separately

Do not handle headset pinctrl along with other pins
needed by codec. If headset related pins are not
present in the target, it might result in sound card
not getting initialized problem.

CRs-Fixed: 642944
Change-Id: I6b4ce44f3eefcd6eda976a93b629f7c75d17e067
Signed-off-by: Simmi Pateriya <simmip@codeaurora.org>