board: nuvoton: update console environment variable

If CONFIG_SYS_SKIP_UART_INIT is enabled, calculate the
current baud rate and update the "console" environment
variable.

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
diff --git a/board/nuvoton/poleg_evb/Kconfig b/board/nuvoton/poleg_evb/Kconfig
index d3f4c1d..6f7f1ef 100644
--- a/board/nuvoton/poleg_evb/Kconfig
+++ b/board/nuvoton/poleg_evb/Kconfig
@@ -22,4 +22,5 @@
 
 endchoice
 
+source "board/nuvoton/common/Kconfig"
 endif