clk: prima2: enable dt-binding clkdev mapping

this patche deletes hard code that registers clkdev by things like:
clk_register_clkdev(clk, NULL, "b0030000.nand");
clk_register_clkdev(clk, NULL, "b0040000.audio");
clk_register_clkdev(clk, NULL, "b0080000.usp");
prima2 clock controller becomes a clock provider and  every dt node
just declares its clock sources by dt prop.

it also makes us easier to extend this driver to support both prima2
and marco as marco has different address mapping with prima2.

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>