defconfig: msm: Add configuration for EDP controller

Currently eDP controller driver is compiled for all targets regardless
controller in HW is present or not. Fix this by adding a config flag
on targets where needed only.

Change-Id: I9a4ae3760b78a2f069462e5092f95356ae34c6ce
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>