ARM: OMAP2+: io: use new clock init API

clk_init is now separated to a common function which gets called for all
SoC:s, which initializes the DT clocks and calls the SoC specific clock init.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>