clk: msm: clock-osm: add OSM clock driver

The Operating State Manager is a hardware block which deals with
performing voltage and frequency change operations in the CPUSS. Two
instances exist, one for each cluster, in the msmcobalt chip.
Introduce the OSM clock driver to perform the required OSM hardware
block initialization and support DCVS scale requests.

Change-Id: I3e155db5cd580e371ca1791815e4942f442a3d20
CRs-Fixed: 967319
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>