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/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