msm: camera: isp: avoid changing camif setting in stop

Previously DUAL_PD_PATH_SEL was set back to pdaf output during stop
sequence. This change avoids changing the register to keep dual pd
path the same before WM stops.

Change-Id: I8647ff6c48b9739b436e6bd5c765df9b5725a977
Signed-off-by: Junzhe Zou <jnzhezou@codeaurora.org>