arm: zynq: Move ZYNQ_SERIAL to Kconfig

Move cadence/zynq serial driver via Kconfig

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/zynq_zc770_xm011_defconfig b/configs/zynq_zc770_xm011_defconfig
index 095ee2f..357b92b 100644
--- a/configs/zynq_zc770_xm011_defconfig
+++ b/configs/zynq_zc770_xm011_defconfig
@@ -33,3 +33,4 @@
 CONFIG_NAND=y
 CONFIG_NAND_ZYNQ=y
 CONFIG_ZYNQ_GEM=y
+CONFIG_ZYNQ_SERIAL=y