Remove reference to including check_config.h

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
diff --git a/configs/README.txt b/configs/README.txt
index 51560fb..9e5a243 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -8,8 +8,6 @@
 them, you can pick one of the following methods:
 
 1. Replace the default file include/mbedtls/mbedtls_config.h with the chosen one.
-   (Depending on your compiler, you may need to adjust the line with
-   #include "mbedtls/check_config.h" then.)
 
 2. Define MBEDTLS_CONFIG_FILE and adjust the include path accordingly.
    For example, using make: