regulator: core.c Pass voltage to notifier when setting voltage

The voltage being set should be passed to the call in handler
requesting the callback.  Currently this is not done.

The calling handler cannot call regulator_get_voltage() to get the
information since the mutex is held by the regulator and
deadlock occurs.

Without this change the receiver of the call in cannot know what
action to take.  This is used, for example, to set PAD voltages
when doing SD vccq voltage changes.

[Review and spelling fix in the commit log from Pankaj Jangra]

Signed-off-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>