clk: nomadik: declare OF clock provider

Common clock framework allows to register clock providers to get called
on of_clk_init() by using CLK_OF_DECLARE. This converts nomadik clock
provider to make use of it and get rid of the mach specific clk init
call. As clocks require system reset controller base address to be
initialized each clock driver checks src_base and calls new
nomadik_src_init if required.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Mike Turquette <mturquette@linaro.org>