bootstd: Enable BOOTSTD_DEFAULTS by default

This is needed to enable the boot command used to start standard boot.
Enable it by default for boards which use BOOTSTD.

This brings in quite a few features, mostly in common with
DISTRO_DEFAULTS

Note: This actually only effects boards which don't have a custom
boot command, so there are no size increases from this patch.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/Kconfig b/boot/Kconfig
index d95a2a7..61ebc27 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -435,6 +435,7 @@
 config BOOTSTD_DEFAULTS
 	bool "Select some common defaults for standard boot"
 	depends on BOOTSTD
+	default y
 	imply USE_BOOTCOMMAND
 	select BOOT_DEFAULTS
 	help