ARM: ks8695: convert to generic time and clocksource

Old platforms using ancient gettimeoffset() and other arcane
APIs are standing in the way of cleaning up the ARM kernel.
The gettimeoffset() was also broken: it would try to read out
the timer counter value, while this would not work (the
counter statically returns the initially programmed value)
so the implementation would anyway fall back to a homebrew
version of jiffie calculation.

This is an attempt at blind-coding a generic time and clocksource
driver for the platform by way of a datasheet and looking at the
old code.

Tested-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>