ARM: dts: dove: Add Compulab SBC-A510 to Makefile

With reworked device tree files for Compulab CM-A510 SoM and SBC-A510
base board, now add the correspoding board file to Makefile again.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>