qcacmn: Add timekeeping.h inclusion under correct kernel version

timekeeping.h is available from kernel version 3.17. Add header
inclusion and ktime_get_boot_ns call under correct version check flag.

Change-Id: I2a1a127e1716b52af56d14c39e2e646e34b05fa3
CRs-Fixed: 2230949
2 files changed