dm: cros_ec: Convert cros_ec keyboard driver to driver model

Adjust the cros_ec keyboard driver to support driver model. Make this the
default for all Exynos boards so that those that use a keyboard will build
correctly with this driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5ab0254..6542c38 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -419,6 +419,7 @@
 	select DM_SERIAL
 	select DM_SPI
 	select DM_GPIO
+	select DM_KEYBOARD
 
 config ARCH_S5PC1XX
 	bool "Samsung S5PC1XX"