Correct documentation references to Mbed TLS

Use the correct formatting of the product name in the documentation.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
diff --git a/include/mbedtls/version.h b/include/mbedtls/version.h
index 648db7e..773da4a 100644
--- a/include/mbedtls/version.h
+++ b/include/mbedtls/version.h
@@ -21,7 +21,7 @@
  */
 /*
  * This set of run-time variables can be used to determine the version number of
- * the mbed TLS library used. Compile-time version defines for the same can be
+ * the Mbed TLS library used. Compile-time version defines for the same can be
  * found in build_info.h
  */
 #ifndef MBEDTLS_VERSION_H