Import some include/linux/clk files from CAF

Import include/linux/clk/msm-clk-provider.h, msm-clk.h, msm-clock-
generic.h from MSM-3.10
Enable footswitch-8x60

Somewhere in between 3.4 and 3.13, include/linux/regulator/driver.h
changed how the regulator_register_function worked. Since footswitch is
based on an old kernel, update it (using drivers/regulator/twl-regulator
as inspiration. *Should* be correct, but will have to double check.