Build: Renable dual-cpu multiple PSA client call feature

The flag to control multiple PSA client call feature doesn't take
effect on dual-cpu platforms in the new build system.
Re-configure it to enable this feature enabled on dual-cpu
platforms.

Change-Id: I3df464c29bec603678b2f05675be141e77dd7fb2
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/config/config_default.cmake b/config/config_default.cmake
index 2364c8e..648c357 100644
--- a/config/config_default.cmake
+++ b/config/config_default.cmake
@@ -54,6 +54,8 @@
 ############################ Platform ##########################################
 
 set(TFM_MULTI_CORE_TOPOLOGY             OFF         CACHE BOOL      "Whether to build for a dual-cpu architecture")
+set(TFM_MULTI_CORE_MULTI_CLIENT_CALL    OFF         CACHE BOOL      "Whether to enable multiple PSA client calls feature")
+
 set(DEBUG_AUTHENTICATION                CHIP_DEFAULT CACHE STRING   "Debug authentication setting. [CHIP_DEFAULT, NONE, NS_ONLY, FULL")
 set(SECURE_UART1                        OFF         CACHE BOOL      "Enable secure UART1")