cnss_utils: Add support to capture LPASS timestamp for wlan audio sync

For FTM based audio sync, hw supports GPIO38 strobe to capture wlan
clock and audio clock into shadow registers. FW uses the clock pair to
derive the master-slave audio clock delta to synchronize audio
between master and slave pair.

Add support to capture LPASS timestamp for wlan audio sync.

Change-Id: If8bf17d95d0ef6e17ca101360e4d8242ba310bfa
Signed-off-by: Govind Singh <govinds@codeaurora.org>