Revert "ARM: dts: msm: configure CX voltage levels from MDSS for msmcobalt"

This reverts 'commit 0754aea0 ("ARM: dts: msm: configure CX voltage
levels from MDSS for msmcobalt")'.

Correctly indicating to the RPM driver when to turn off the MMSS
GDSC. 'commit f1b5dbb743b3 ("msm: mdss: control when MMSS
GDSC gets turned off")' is the correct fix for this issue.

Crs-Fixed: 1068650
Change-Id: I7eae1fbad8467e36c1a216d1ea719c6e3ed9e586
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>