ARM: nomadik: convert to generic clock

Remove more custom stuff by simply converting the Nomadik machine
to use generic clocks and move the driver to drivers/clk.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Mike Turquette <mturquette@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>