Fix multiple quality issues in the source

This PR fixes multiple issues in the source code to address issues raised by
tests/scripts/check-files.py. Specifically:
 * incorrect file permissions
 * missing newline at the end of files
 * trailing whitespace
 * Tabs present
 * TODOs in the souce code
diff --git a/include/mbedtls/ecp_internal.h b/include/mbedtls/ecp_internal.h
index 8a6d517..1804069 100644
--- a/include/mbedtls/ecp_internal.h
+++ b/include/mbedtls/ecp_internal.h
@@ -48,7 +48,7 @@
  * [6] Digital Signature Standard (DSS), FIPS 186-4.
  *     <http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf>
  *
- * [7] Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer 
+ * [7] Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer
  *     Security (TLS), RFC 4492.
  *     <https://tools.ietf.org/search/rfc4492>
  *
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
old mode 100755
new mode 100644
index 7f6da05..42e0dcb
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1828,21 +1828,21 @@
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 /**
- * \brief          Set or reset the hostname to check against the received 
- *                 server certificate. It sets the ServerName TLS extension, 
+ * \brief          Set or reset the hostname to check against the received
+ *                 server certificate. It sets the ServerName TLS extension,
  *                 too, if that extension is enabled. (client-side only)
  *
  * \param ssl      SSL context
  * \param hostname the server hostname, may be NULL to clear hostname
- 
+ *
  * \note           Maximum hostname length MBEDTLS_SSL_MAX_HOST_NAME_LEN.
  *
- * \return         0 if successful, MBEDTLS_ERR_SSL_ALLOC_FAILED on 
- *                 allocation failure, MBEDTLS_ERR_SSL_BAD_INPUT_DATA on 
+ * \return         0 if successful, MBEDTLS_ERR_SSL_ALLOC_FAILED on
+ *                 allocation failure, MBEDTLS_ERR_SSL_BAD_INPUT_DATA on
  *                 too long input hostname.
  *
  *                 Hostname set to the one provided on success (cleared
- *                 when NULL). On allocation failure hostname is cleared. 
+ *                 when NULL). On allocation failure hostname is cleared.
  *                 On too long input failure, old hostname is unchanged.
  */
 int mbedtls_ssl_set_hostname( mbedtls_ssl_context *ssl, const char *hostname );
diff --git a/include/mbedtls/ssl_ciphersuites.h b/include/mbedtls/ssl_ciphersuites.h
index 545468a..1d2aabc 100644
--- a/include/mbedtls/ssl_ciphersuites.h
+++ b/include/mbedtls/ssl_ciphersuites.h
@@ -267,7 +267,7 @@
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)      ||       \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED)     ||       \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)    ||       \
-    defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) 
+    defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
 #define MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED
 #endif