defconfig: sa2150p: enable graphics driver

There is no dedicated CDT for CDP used with telematics
builds. Removing driver entry in kernel config and
device tree needs to go hand in hand which is not
possible as there is no DTS. Therefore enable the
device tree nodes for now.

Change-Id: I68096ecbb0e41d28d8e4468e5a5b517b4a504b12
Signed-off-by: Rishi Gupta <rishgupt@codeaurora.org>