tests: Add mbedtls_test_ prefix to platform_* functions

Add mbedtls_test_ prefix to platform_setup() and
platform_teardown() test helper functions.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/src/helpers.c b/tests/src/helpers.c
index b5ca1f8..dc022ff 100644
--- a/tests/src/helpers.c
+++ b/tests/src/helpers.c
@@ -24,7 +24,7 @@
 static mbedtls_platform_context platform_ctx;
 #endif
 
-int platform_setup( void )
+int mbedtls_test_platform_setup( void )
 {
     int ret = 0;
 #if defined(MBEDTLS_PLATFORM_C)
@@ -33,7 +33,7 @@
     return( ret );
 }
 
-void platform_teardown( void )
+void mbedtls_test_platform_teardown( void )
 {
 #if defined(MBEDTLS_PLATFORM_C)
     mbedtls_platform_teardown( &platform_ctx );