ipq806x: Enable ubi image for ipq40xx AP-DK04.1-C1 board

This change add IPQ40xx AP-DK04.1-C1 board image support,
enables ubi image for IPQ40xx AP-DK04.1-C1 board and also
add sysupgrage support for AP-DK04.1-C1 and generates a
sysupgrade.tar image.

Testing:
 *Tested on IPQ40xx AP-DK04.1-C1:
   a. NAND boot
   b. ubi sysupgrade

Signed-off-by: Ram Chandra Jangir <rjangir@codeaurora.org>