ARM: OMAP5: Add hook in SoC initcalls to enable pm initialization

With consolidated code, now we can add the required hooks for
OMAP5 to enable power management.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[nm@ti.com: minor rebase updates]
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>