ARM: dts: msm: enable edp device node

Enable edp panel device nodes by default so
they are available for the respective controllers
to initialize when required. This allows to implement
the ability to override the choice of default primary
display panel which can be used for panel characterization
purposes.

Change-Id: I5056e10a406aec4e8033da4b3476c01887f0c68c
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>