clk: msm: clock-osm: support trace packet config through debugfs

Add a debugfs interface to enable and configure OSM debug trace
packet generation. There are four different supported OSM packet
IDs and two tracing modes. The supported sysfs files and their
corresponding values are:

trace_enable		[0, 1]
trace_method		[xor, periodic]
trace_packet_id		[0, 1, 2, 3]
trace_periodic_timer	[1 - 20000000] (us)

Unless otherwised modified through trace_periodic_timer, the
default periodic timer is set to 1 millisecond.

Change-Id: I82b7f78bac7379e9a647b5c8e68c356cd1d5c863
CRs-Fixed: 987787
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>