regulators: Add phosphor-regulators service dependencies

'regsctl' can't do anything useful until phosphor-regulators is running,
so add systemd unit dependencies to ensure it's started before
regulators-config and regulators-monitor-{enable,disable}.

While we're at it, change phosphor-regulators.service to be of type dbus
so we get a more meaningful check that it's really up and running, and
tweak the instantiation of ManagerObject so that it emits the necessary
signals.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Change-Id: I724e4f335c4347ad6789e2d68cfb58c6387e6073
diff --git a/services/phosphor-regulators.service b/services/phosphor-regulators.service
index a7680dc..f089df9 100644
--- a/services/phosphor-regulators.service
+++ b/services/phosphor-regulators.service
@@ -4,6 +4,8 @@
 After=obmc-mapper.target
 
 [Service]
+Type=dbus
+BusName=xyz.openbmc_project.Power.Regulators
 Restart=on-failure
 ExecStart=/usr/bin/phosphor-regulators