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/xilinx_zynqmp_zc1751_xm016_dc2_defconfig b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
index 37b0185..8c8201d 100644
--- a/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
+++ b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
@@ -60,6 +60,7 @@
 CONFIG_DEBUG_UART_BASE=0xff000000
 CONFIG_DEBUG_UART_CLOCK=100000000
 CONFIG_DEBUG_UART_ANNOUNCE=y
+CONFIG_ZYNQ_SERIAL=y
 CONFIG_USB=y
 CONFIG_USB_XHCI_HCD=y
 CONFIG_USB_XHCI_DWC3=y