Kconfig: boot: Imply BOOTSTD_DEFAULT when BOOTSTD_FULL=y

We need BOOTSTD_DEFAULT when BOOTSTD_FULL is selected.

Signed-off-by: Shantur Rathore <i@shantur.com>
diff --git a/boot/Kconfig b/boot/Kconfig
index 70ff248..71ee416 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -426,6 +426,7 @@
 config BOOTSTD_FULL
 	bool "Enhanced features for standard boot"
 	default y if SANDBOX
+	imply BOOTSTD_DEFAULTS
 	help
 	  This enables various useful features for standard boot, which are not
 	  essential for operation: