ARM: dts: msm: Move to enabling GDSC control on SDM855

The GDSCs are currently modelled as dummy regulators on SDM855.
Update their compatible properties to enable controlling them
from the GDSC regulator driver.

Change-Id: I887f491ecfb6233cc36006eaf36b6c519367dbbb
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>