firmware: arm_scpi: Add hardware dependencies

With a name like that, I assume that the ARM SCPI protocol is only
useful on the ARM architectures.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NSudeep Holla <sudeep.holla@arm.com>
Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

drivers/firmware/Kconfig

@@ -21,6 +21,7 @@ config ARM_PSCI_CHECKER
 
 config ARM_SCPI_PROTOCOL
 	tristate "ARM System Control and Power Interface (SCPI) Message Protocol"
+	depends on ARM || ARM64 || COMPILE_TEST
 	depends on MAILBOX
 	help
 	  System Control and Power Interface (SCPI) Message Protocol is