ARM: dts: msm: Add stub regulators for msmthorium

Stub regulators have no dependencies on hardware,
add stub regulator devices so that regulator
consumers can reference them.

Change-Id: Ifae7aeaea768a07db8d9af2b0806da6651170159
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>