STiH410: Add STi serial driver

This patch adds support to ASC (asynchronous serial controller)
driver, which is basically a standard serial driver. This IP
is common across other STMicroelectronics SoCs

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c9a2968..bde969d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1096,6 +1096,8 @@
 config ARCH_STI
 	bool "Support STMicrolectronics SoCs"
 	select CPU_V7
+	select DM
+	select DM_SERIAL
 	help
 	  Support for STMicroelectronics STiH407/10 SoC family.
 	  This SoC is used on Linaro 96Board STiH410-B2260