UPSTREAM: regulator: core: Add support for active-discharge configuration

UPSTREAM: regulator: core: Add support for active-discharge configuration

Add support to enable/disable active discharge of regulator via
machine constraints. This configuration is done when setting
machine constraint during regulator register and if regulator
driver implemented the callback ops.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
(cherry picked from commit 670666b9e0aff40c65d8061a2f53e79eee238685)

Change-Id: I5e22602d9a44b88482922ae0a726fd0d8f374e0a
Signed-off-by: David Wu <david.wu@rock-chips.com>