tests: suites: Remove `hex` in name of variables of type data_t

Remove `hex` in name of variables of type data_t to reserve it
for variables of type char* that are the hexadecimal
representation of a data buffer.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/suites/test_suite_arc4.function b/tests/suites/test_suite_arc4.function
index 9aa4913..c1e2386 100644
--- a/tests/suites/test_suite_arc4.function
+++ b/tests/suites/test_suite_arc4.function
@@ -8,8 +8,7 @@
  */
 
 /* BEGIN_CASE */
-void mbedtls_arc4_crypt( data_t * src_str, data_t * key_str,
-                         data_t * hex_dst_string )
+void mbedtls_arc4_crypt( data_t * src_str, data_t * key_str, data_t * dst )
 {
     unsigned char dst_str[1000];
     mbedtls_arc4_context ctx;
@@ -19,11 +18,11 @@
 
 
     mbedtls_arc4_setup(&ctx, key_str->x, key_str->len);
-    TEST_ASSERT( mbedtls_arc4_crypt(&ctx, src_str->len, src_str->x, dst_str ) == 0 );
+    TEST_ASSERT( mbedtls_arc4_crypt(&ctx, src_str->len,
+                                    src_str->x, dst_str ) == 0 );
 
-    TEST_ASSERT( mbedtls_test_hexcmp( dst_str, hex_dst_string->x,
-                                      src_str->len,
-                                      hex_dst_string->len ) == 0 );
+    TEST_ASSERT( mbedtls_test_hexcmp( dst_str, dst->x,
+                                      src_str->len, dst->len ) == 0 );
 
 exit:
     mbedtls_arc4_free( &ctx );