ARM: OMAP3: hwmod: initialize clkdm from clkdm_name

DT clocks are mostly missing clkdm info now, and this causes an issue with
counter32k which makes its slave idlemode wrong and prevents core idle.

Fixed by initializing the hwmod clkdm pointers for omap3 also which makes
sure the clkdm flag matching logic works properly.

This patch also changes the return value for _init_clkdm to 0 for
incorrect clkdm_name, as this a warning, not a fatal error.

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