Convert gpio api's to gpio descriptor api's in CTIA/OMTP switch control.
Remove redundant NULL checks in swap_gnd_mic function.

Fixes: 013cc2ae ("ASoC: codec: wcd938x: Add switch control for selecting CTIA/OMTP Headset")
Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
Co-developed-by: Venkata Prasad Potturu <quic_potturu@quicinc.com>
Signed-off-by: Venkata Prasad Potturu <quic_potturu@quicinc.com>
Link: https://lore.kernel.org/r/1645017892-12522-1-git-send-email-quic_srivasam@quicinc.comSigned-off-by: Mark Brown <broonie@kernel.org>