ARM: OMAP2+: hwmod: populate clkctrl clocks for hwmods if available

If clkctrl clocks are available on a device, populate these automatically
to replace hwmod main_clk info. First, the patch parses all "ti,clkctrl"
compatible nodes and maps these against existing clockdomain data. Once
done, individual hwmod init routines can search for a clkctrl clock
handle based on the clockdomain info and the created mapping.

This patch also drops the obsolete "_mod_ck" search as the implementation
required for this was not accepted usptream.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>