at91: vinco: Enable DM_SPI

AT91 Vinco board uses atmel spi driver, enable DM_SPI to
use dm functionality.

Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index b9e6946..17d60d0 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -238,6 +238,7 @@
 	select SAMA5D4
 	select SUPPORT_SPL
 	select DM
+	select DM_SPI
 
 config TARGET_WB45N
 	bool "Support Laird WB45N"