Remove internal file references in programs/

`entropy_poll.h` and `md_wrap.h` were still being used in some of the
example programs. As these headers are now internal, remove their
references and replace them with publicly available functions.

Signed-off-by: Chris Jones <christopher.jones@arm.com>

include/mbedtls/entropy.h

@@ -134,6 +134,14 @@ typedef struct mbedtls_entropy_context
 }
 mbedtls_entropy_context;
 
+#if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+/**
+ * \brief           Platform-specific entropy poll callback
+ */
+int mbedtls_platform_entropy_poll( void *data,
+                           unsigned char *output, size_t len, size_t *olen );
+#endif
+
 /**
  * \brief           Initialize the context
  *

programs/ssl/ssl_context_info.c

@@ -48,7 +48,6 @@ int main( void )
 #include "mbedtls/error.h"
 #include "mbedtls/base64.h"
 #include "mbedtls/md.h"
-#include "../../library/md_wrap.h"
 #include "mbedtls/x509_crt.h"
 #include "mbedtls/ssl_ciphersuites.h"
 
@@ -638,7 +637,7 @@ void print_deserialized_ssl_session( const uint8_t *ssl, uint32_t len,
         }
         else
         {
-            printf( "\tMessage-Digest : %s\n", md_info->name );
+            printf( "\tMessage-Digest : %s\n", mbedtls_md_get_name( md_info ) );
         }
     }
 

programs/test/selftest.c

@@ -55,7 +55,6 @@
 #include "mbedtls/ecjpake.h"
 #include "mbedtls/timing.h"
 #include "mbedtls/nist_kw.h"
-#include "../library/entropy_poll.h"
 
 #include <string.h>