Removes target_config.h file from default and thread configs

target_config.h is no longer needed for target/platform configurations so
this change removes it from the default and platform configurations for mbed
builds.
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index b1f2451..ab351fb 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2572,11 +2572,7 @@
 /* X509 options */
 //#define MBEDTLS_X509_MAX_INTERMEDIATE_CA   8   /**< Maximum number of intermediate CAs in a verification chain. */
 
-/* \} name SECTION: Module configuration options */
-
-#if defined(TARGET_LIKE_MBED)
-#include "mbedtls/target_config.h"
-#endif
+/* \} name SECTION: Customisation configuration options */
 
 /*
  * Allow user to override any previous default.