xilinx: zynq: Enable DCC and create new zynq_dcc board

Enable DCC driver for arm zynq platform to be compiled.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/boards.cfg b/boards.cfg
index 98f7a14..1d30a18 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -296,6 +296,7 @@
 kzm9g                        arm         armv7       kzm9g               kmc            rmobile
 armadillo-800eva             arm         armv7       armadillo-800eva    atmark-techno  rmobile
 zynq                         arm         armv7       zynq                xilinx         zynq
+zynq_dcc                     arm         armv7       zynq                xilinx         zynq        zynq:ZYNQ_DCC
 socfpga_cyclone5                arm         armv7          socfpga_cyclone5    altera		    socfpga
 actux1_4_16                  arm         ixp         actux1              -              -           actux1:FLASH2X2
 actux1_4_32                  arm         ixp         actux1              -              -           actux1:FLASH2X2,RAM_32MB