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_microzed_defconfig b/configs/zynq_microzed_defconfig
index a6a37f8..a713314 100644
--- a/configs/zynq_microzed_defconfig
+++ b/configs/zynq_microzed_defconfig
@@ -46,6 +46,7 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_ZYNQ_GEM=y
+CONFIG_ZYNQ_SERIAL=y
 CONFIG_ZYNQ_QSPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y