Include ssl_misc.h for additional SSL helper files

This commit replaces #include "common.h" in favour of #include
"ssl_misc.h".

Signed-off-by: Harry Ramsey <harry.ramsey@arm.com>
diff --git a/library/debug.c b/library/debug.c
index c36ed3c..a486353 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -5,7 +5,7 @@
  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */
 
-#include "common.h"
+#include "ssl_misc.h"
 
 #if defined(MBEDTLS_DEBUG_C)