ARM: dts: msm8974: Remove obsolete nodes

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
ARM: dts: msm: Update MDP writeback QoS configuration

Right now, writeback QoS registers are being programmed dynamically
when respective paths are being exercised. Starting 8916, wb QoS
is starting to differ from other chip-sets and since these are
chip-set specific settings, hence configure them using device-tree.

Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
defconfig: Enable MSM_RTB

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>