App: Remove unused header

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I89db5def9ea1c181b9e79270850ca47e5e20745e
diff --git a/app/main_ns.c b/app/main_ns.c
index c52a859..e153572 100644
--- a/app/main_ns.c
+++ b/app/main_ns.c
@@ -16,7 +16,6 @@
 #ifdef PSA_API_TEST_NS
 #include "psa_api_test.h"
 #endif
-#include "target_cfg.h"
 #include "tfm_plat_ns.h"
 #include "driver/Driver_USART.h"
 #include "device_cfg.h"