arm: dt: apq8026: add DT support for apq8026

Add the device tree files for apq8026 and update the DT match table
in the board file to recognize the new device tree files. Makefile
support is also needed to compile the new DTBs.

Change-Id: I6e11796256a6379b7b9211e8d8350906600b80aa
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>