sandbox: enable button

Enable the support of button (driver and command) on sandbox.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index b30f1e3..5bb44c7 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -108,6 +108,8 @@
 CONFIG_BOOTCOUNT_LIMIT=y
 CONFIG_DM_BOOTCOUNT=y
 CONFIG_DM_BOOTCOUNT_RTC=y
+CONFIG_BUTTON=y
+CONFIG_BUTTON_GPIO=y
 CONFIG_CLK=y
 CONFIG_CLK_COMPOSITE_CCF=y
 CONFIG_SANDBOX_CLK_CCF=y