Build module with cmake

Change-Id: I294f6ad22881254a8b0fef45b875fe0e12c91e7a
diff --git a/mailbox/Kconfig b/mailbox/Kconfig
index 9cfce3e..e7a9cba 100644
--- a/mailbox/Kconfig
+++ b/mailbox/Kconfig
@@ -1,5 +1,5 @@
 #
-# (C) COPYRIGHT 2020 ARM Limited. All rights reserved.
+# (C) COPYRIGHT 2020 Arm Limited. All rights reserved.
 #
 # This program is free software and is provided to you under the terms of the
 # GNU General Public License version 2 as published by the Free Software
@@ -19,11 +19,17 @@
 #
 
 config ARM_MHU
-        tristate "ARM MHU Mailbox"
+        tristate "Arm MHU Mailbox"
         depends on ARM_AMBA
         help
-          Say Y here if you want to build the ARM MHU controller driver.
+          Say Y here if you want to build the Arm MHU controller driver.
           The controller has support for two versions of the controller.
 	  One with 3 mailbox channels, the last of which can be
           used in Secure mode only and one with a single channel.
 
+config ARM_MHU_V2
+	tristate "Arm MHUv2 Mailbox"
+	depends on ARM_AMBA
+	help
+	  Say Y here if you want to build the Arm MHUv2 controller driver,
+	  which provides unidirectional mailboxes between processing elements.