sandbox: Finish migration to Kconfig

Stop using CONFIG_SANDBOX_ARCH and use CONFIG_SANDBOX instead. For the
SPI related defines, set them directly in Kconfig. This now empties
arch/sandbox/include/asm/config.h.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/adc/adc-uclass.c b/drivers/adc/adc-uclass.c
index 67137ff..9646e4d 100644
--- a/drivers/adc/adc-uclass.c
+++ b/drivers/adc/adc-uclass.c
@@ -22,7 +22,7 @@
 #define CHECK_MASK			(!CHECK_NUMBER)
 
 /* TODO: add support for timer uclass (for early calls) */
-#ifdef CONFIG_SANDBOX_ARCH
+#ifdef CONFIG_SANDBOX
 #define sdelay(x)	udelay(x)
 #else
 extern void sdelay(unsigned long loops);