ARM: dts: msm: specify VDD_GFX CPR voltage adjustments for msm8996

Device characterization has shown that some of the open-loop
voltages and target quotients for VDD_GFX on msm8996 need
adjustment in order to ensure optimal voltage margin for all
corners.

Specify ring oscillator scaling factors, open-loop voltage
adjustments, and closed-loop voltage adjustments which match
the characterization data.

Change-Id: I0455d73a1f248b0e25129fd4a66b49af7f3973de
Signed-off-by: David Collins <collinsd@codeaurora.org>