ARM: dts: msm: remove CX and GFX explicit voltage support on msmsamarium

Remove device nodes which provide explicit voltage support for
the VDD_CX (SMPS 2) and VDD_GFX (SMPS 7) regulators on
msmsamarium.  This support needs to be removed because the RPM
will soon be removing support for explicit voltage requests made
for these regulators.

Change all consumer supply properties which point to pma8084_s2
to use pma8084_s2_corner instead.  This does not impact camera
operation because the camera only manages the mode and not the
voltage of VDD_CX.

Change-Id: Ief311b8cf97b01492262242d5cc2db59acb730b1
Signed-off-by: David Collins <collinsd@codeaurora.org>