arm: juno: Use PSCI based reset

So far the Juno board wasn't implementing reset. Let's just use the
already existing PSCI_RESET based method to avoid any extra code.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 27ae0a8..7c58912 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1167,6 +1167,8 @@
 	select OF_BOARD
 	select CLK
 	select DM_SERIAL
+	select ARM_PSCI_FW
+	select PSCI_RESET
 
 config TARGET_LS2080A_EMU
 	bool "Support ls2080a_emu"