Fix typo in ssl_internal.h

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 2c30855..c6847ba 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -392,7 +392,7 @@
  *
  * Since the current definitions of MBEDTLS_MAX_{KEY|BLOCK|IV}_LENGTH
  * in cipher.h are rough overapproximations of the real maxima, here
- * we content ourselves with defining replicating those overapproximations
+ * we content ourselves with replicating those overapproximations
  * for the maximum block and IV length, and excluding XTS from the
  * computation of the maximum key length. */
 #define MBEDTLS_SSL_MAX_BLOCK_LENGTH 16