ARM: dts: msm: add a fixed regulator to represent vdd of CTP

On Huawei EVT2 board, VDD supply for Synaptics S3207A touch
controller is powered up by the same regulator that supplies
the pull up for touch controller. A fixed regulator device
node is added to represent the Vdd regulator to make the dtsi
definition compatitable with the CTP driver.

Change-Id: I0edec82390ee459ed11bf28e80bcb95f126c2ac0
Signed-off-by: Mao Li <maol@codeaurora.org>