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: NMasami Hiramatsu <masami.hiramatsu@linaro.org>

configs/synquacer_developerbox_defconfig

@@ -92,3 +92,4 @@ CONFIG_EFI_SET_TIME=y
 CONFIG_EFI_RUNTIME_UPDATE_CAPSULE=y
 CONFIG_EFI_CAPSULE_ON_DISK=y
 CONFIG_EFI_CAPSULE_FIRMWARE_FIT=y
+CONFIG_EFI_SECURE_BOOT=y