Build: Disable SPM Model specific test suites

This patch disables SPM Model specific test suites by default
and enables them respectively, to make the set_config.cmake simpler.

Change-Id: Ic0a7c311c9d298bc62886106d8136a73c7622e9c
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/test/config/default_s_test_config.cmake b/test/config/default_s_test_config.cmake
index b2a8575..05ad57a 100644
--- a/test/config/default_s_test_config.cmake
+++ b/test/config/default_s_test_config.cmake
@@ -17,6 +17,7 @@
 set(TEST_S_ITS              ON        CACHE BOOL      "Whether to build S regression ITS tests")
 set(TEST_S_PS               ON        CACHE BOOL      "Whether to build S regression PS tests")
 set(TEST_S_PLATFORM         ON        CACHE BOOL      "Whether to build S regression Platform tests")
+
 set(TEST_S_FWU              OFF       CACHE BOOL      "Whether to build S regression FWU tests")
-set(TEST_S_IPC              ON        CACHE BOOL      "Whether to build S regression IPC tests")
+set(TEST_S_IPC              OFF       CACHE BOOL      "Whether to build S regression IPC tests")
 set(TEST_S_FPU              OFF       CACHE BOOL      "Whether to build S regression FPU tests")