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/docs/3.0-migration-guide.d/split_config.md b/docs/3.0-migration-guide.d/split_config.md
index b011ad7..ced3896 100644
--- a/docs/3.0-migration-guide.d/split_config.md
+++ b/docs/3.0-migration-guide.d/split_config.md
@@ -10,8 +10,8 @@
 macro.
 
 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`.