firmware: meson-sm: enable build as module

Enable secure module driver as module.
Default remains built-in.
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

drivers/firmware/meson/Kconfig

@@ -3,8 +3,9 @@
 # Amlogic Secure Monitor driver
 #
 config MESON_SM
-	bool
-	default ARCH_MESON
+	tristate "Amlogic Secure Monitor driver"
+	depends on ARCH_MESON || COMPILE_TEST
+	default y
 	depends on ARM64_4K_PAGES
 	help
 	  Say y here to enable the Amlogic secure monitor driver

drivers/firmware/meson/meson_sm.c

@@ -331,3 +331,4 @@ static struct platform_driver meson_sm_driver = {
 	},
 };
 module_platform_driver_probe(meson_sm_driver, meson_sm_probe);
+MODULE_LICENSE("GPL v2");