configs: synquacer: Enable UEFI secure boot

Enable UEFI secure boot on synquacer. Note that unless user
setup their keys, the secure boot will not work.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
diff --git a/configs/synquacer_developerbox_defconfig b/configs/synquacer_developerbox_defconfig
index 3aa507f..da5714d 100644
--- a/configs/synquacer_developerbox_defconfig
+++ b/configs/synquacer_developerbox_defconfig
@@ -92,3 +92,4 @@
 CONFIG_EFI_RUNTIME_UPDATE_CAPSULE=y
 CONFIG_EFI_CAPSULE_ON_DISK=y
 CONFIG_EFI_CAPSULE_FIRMWARE_FIT=y
+CONFIG_EFI_SECURE_BOOT=y