MLECO-2985 Adding Corstone-310 support

Change-Id: Ifa4b11154478355c10cb3e747b9938a74afd242b
Signed-off-by: Eanna O Cathain <eanna.ocathain@arm.com>
diff --git a/scripts/cmake/common_user_options.cmake b/scripts/cmake/common_user_options.cmake
index 7dc68de..7981068 100644
--- a/scripts/cmake/common_user_options.cmake
+++ b/scripts/cmake/common_user_options.cmake
@@ -43,7 +43,7 @@
     mps3
     STRING)
 
-USER_OPTION(TARGET_SUBSYSTEM "Specify platform target subsystem: sse-300 or none"
+USER_OPTION(TARGET_SUBSYSTEM "Specify platform target subsystem: sse-300, sse-310 or none"
     sse-300
     STRING)