Interface: Rename PSA headers

Renames PSA headers from psa_<api>.h to psa/<api>.h.

Change-Id: I3fc552c39f9a7e6d54e7a7a2f82f076bd03d30a7
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
diff --git a/interface/src/tfm_psa_ns_api.c b/interface/src/tfm_psa_ns_api.c
index 159eef9..838e7b0 100644
--- a/interface/src/tfm_psa_ns_api.c
+++ b/interface/src/tfm_psa_ns_api.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2018, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2019, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
  */
 
-#include "interface/include/psa_client.h"
+#include "psa/client.h"
 #include "tfm_ns_lock.h"
 #include "tfm_api.h"
 
@@ -72,4 +72,3 @@
                          0,
                          0);
 }
-