Remove mbedtls_param_failed from programs

All sample and test programs had a definition of mbedtls_param_failed.
This was necessary because we wanted to be able to build them in a
configuration with MBEDTLS_CHECK_PARAMS set but without a definition
of MBEDTLS_PARAM_FAILED. Now that we activate the sample definition of
MBEDTLS_PARAM_FAILED in config.h when testing with
MBEDTLS_CHECK_PARAMS set, this boilerplate code is no longer needed.

programs/ssl/ssl_fork_server.c

@@ -87,17 +87,6 @@ int main( void )
 
 #define DEBUG_LEVEL 0
 
-#if defined(MBEDTLS_CHECK_PARAMS)
-#include "mbedtls/platform_util.h"
-void mbedtls_param_failed( const char *failure_condition,
-                           const char *file,
-                           int line )
-{
-    mbedtls_printf( "%s:%i: Input param failed - %s\n",
-                    file, line, failure_condition );
-    mbedtls_exit( MBEDTLS_EXIT_FAILURE );
-}
-#endif
 
 static void my_debug( void *ctx, int level,
                       const char *file, int line,