Call mbed_tfm_init earlier

Change-Id: I2a7b33cd2254a79986f0318a7099232487c0a42a
Signed-off-by: Mark Horvath <mark.horvath@arm.com>

Author: mark-horvath-arm

rtos/source/TARGET_CORTEX/mbed_boot.c

@@ -95,8 +95,8 @@ void mbed_init(void)
 void mbed_start(void)
 {
     mbed_rtos_init_singleton_mutex();
-    mbed_toolchain_init();
     mbed_tfm_init();
+    mbed_toolchain_init();
     mbed_main();
     mbed_error_initialize();
     main();