msm: clk-provider: Move clock headers to include/linux/clk

Architecutural changes in the ARM Linux kernel tree mandate the
eventual removal of the mach-* directories. Move the
mach/clk-provider and mach/clk header to include/linux/clk.

Change-Id: I495f8332bf5d0d09ccfb236c819dea2bacb13542
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>