clk: qcom: Add support to record clock state using ftrace

Add ftrace event so that the state of all the clocks can be recorded
using ftrace. Use that event to add support in debugfs to take a
snapshot of all the clocks present and their current state to ftrace.

CRs-Fixed: 766583
Change-Id: Ibe95b5eaa013e2da378b9dc5e8c43162895ef272
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>