RPC: Merge RPC PSA Client APIs

Originally, connection-based APIs are optional, depends on whether the
TF-M provides any.
So the RPC APIs are also separated so that they can be selected.

Later, the APIs are always provided with returning NOT SUPPORTED in case
of no connection-based APIs.
And the RPC test framework followed up by always building all the APIs.

This patch makes it further by merging all the APIs.

Change-Id: I923c24e5e83cae4e3d8f4774d776dbe8d07610c2
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/erpc/host_example/main.c b/erpc/host_example/main.c
index 1545525..c2d1357 100644
--- a/erpc/host_example/main.c
+++ b/erpc/host_example/main.c
@@ -10,7 +10,7 @@
 #include <string.h>
 #include "erpc_port.h"
 #include "erpc_client_start.h"
-#include "tfm_erpc_psa_client_api.h"
+#include "tfm_erpc.h"
 #include "tfm_crypto_defs.h"
 #include "psa/client.h"
 #include "psa/crypto.h"