regulator: core: Increase refcount for regulator supply's module

When a regulator is unregistered with regulator_unregister(), a call to
regulator_put() is made for its input supply if there is one. This does
a module_put() to decrement the refcount of the module that owns the
supply but there isn't a corresponding try_module_get() in set_supply()
to make the calls balanced.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>