ANDROID: GKI: regulator: core: Add support for regulator providers with sync state

Regulator providers whose drivers have sync_state() implemented will
disable their regulators once all their consumers have probed. So during
late_initcall_sync(), don't disable unused regulators of these regulator
providers.

Also, provide a regulator_sync_state() API that regulator providers can
use to disable all their unused regulators once the get their
sync_state() callback.

Bug: 144127090
Bug: 150508586
Signed-off-by: Saravana Kannan <saravanak@google.com>
Change-Id: I5cc32730214c8e769c2a55cbe3b702cf6bb9016a