Change mbedtls_entropy_func in tests to mbedtls_test_entropy_func

Change function in tests named mbedtls_entropy_func to
mbedtls_test_entropy_func to avoid getting error from the linker when
calling the mbedtls_entropy_func elsewhere.
diff --git a/tests/suites/test_suite_hmac_drbg.function b/tests/suites/test_suite_hmac_drbg.function
index 5209470..a413f5e 100644
--- a/tests/suites/test_suite_hmac_drbg.function
+++ b/tests/suites/test_suite_hmac_drbg.function
@@ -7,7 +7,7 @@
     size_t len;
 } entropy_ctx;
 
-int mbedtls_entropy_func( void *data, unsigned char *buf, size_t len )
+static int mbedtls_test_entropy_func( void *data, unsigned char *buf, size_t len )
 {
     entropy_ctx *ctx = (entropy_ctx *) data;
 
@@ -50,7 +50,7 @@
 
     /* Init must use entropy */
     last_len = entropy.len;
-    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &entropy,
+    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &entropy,
                                  NULL, 0 ) == 0 );
     TEST_ASSERT( entropy.len < last_len );
 
@@ -206,7 +206,7 @@
     TEST_ASSERT( memcmp( my_output, output, out_len ) == 0 );
 
     /* And now the normal entropy-based variant */
-    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
+    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
                                  custom, custom_len ) == 0 );
     TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                             add1, add1_len ) == 0 );
@@ -251,7 +251,7 @@
     md_info = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md_info != NULL );
 
-    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
+    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
                                  custom, custom_len ) == 0 );
     TEST_ASSERT( mbedtls_hmac_drbg_reseed( &ctx, add1, add1_len ) == 0 );
     TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
@@ -296,7 +296,7 @@
     md_info = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md_info != NULL );
 
-    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
+    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
                                  custom, custom_len ) == 0 );
     mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
     TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,