clk: ti: Initialize clocks for dm816x

The clocks on ti81xx are not compatible with omap3. On dm816x
the clock source is a FAPLL (Flying Adder PLL), and on dm814x
there seems to be an APLL (All Digital PLL).

Let's fix up things for dm816x in preparation for adding the
FAPLL support. As we already have a dummy ti81xx_dt_clk_init()
in place, let's use that for now to avoid adding a dependency
to the omap patches.

Later on if somebody adds dm814x support we can split the
ti81xx_dt_clk_init() clock init function as needed.

Cc: Brian Hutchinson <b.hutchman@gmail.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>