clk: msm: Copy parts of mach-msm/clock.h to drivers/clk/msm/

Patches in the near future will be moving MSM specific
clock libraries and clock framework implementations to
drivers/clk/msm. In preparation for this, copy over some
declarations from mach-msm/clock.h to drivers/clk/msm/

Change-Id: I24a294928c44fec9743262ae9fd646748c0e9d0c
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>