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/ChangeLog.d/split-config.txt b/ChangeLog.d/split-config.txt
index 5d1201c..f66dc93 100644
--- a/ChangeLog.d/split-config.txt
+++ b/ChangeLog.d/split-config.txt
@@ -6,8 +6,8 @@
      build_info.h.
    * The handling of MBEDTLS_CONFIG_FILE has been moved into build_info.h.
    * A config file version symbol, MBEDTLS_CONFIG_VERSION was introduced.
-     Defining it to a particular value will ensure that mbedtls interprets
+     Defining it to a particular value will ensure that Mbed TLS interprets
      the config file in a way that's compatible with the config file format
-     used by the mbedtls release whose MBEDTLS_VERSION_NUMBER has the same
+     used by the Mbed TLS release whose MBEDTLS_VERSION_NUMBER has the same
      value.
-     The only value supported by mbedtls 3.0.0 is 0x03000000.
+     The only value supported by Mbed TLS 3.0.0 is 0x03000000.