ARM: dts: OMAP3+: add clock nodes for CPU

OMAP34xx, AM3517 and OMAP36xx platforms use dpll1 clock.

OMAP443x, OMAP446x, OMAP447x, OMAP5, DRA7, AM43xx platforms use
dpll_mpu clock.

Latency used is the generic latency defined in omap-cpufreq
driver.

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