Some boards have to initialize the PMIC before other devices can
be initialized. This requires three levels of initcalls: one level
in which the PMIC is probed, one in which the board can call mc13xxx_get()
and the third one to initialize the PMIC dependent devices.
Allow to register a callback which is called once the PMIC is initialized.
This way mc13xxx_get() is no longer necessary and the number of required
initcalls levels is reduced to two.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>