Update configs README

This commit updates configs/README.txt and configs/ext/README.md to
reflect the necessary files which were moved to TF-PSA-Crypto.

Signed-off-by: Harry Ramsey <[email protected]>

configs/README.txt

@@ -0,0 +1,20 @@
+This directory contains example configuration files.
+
+The examples are generally focused on a particular usage case (eg, support for
+a restricted number of ciphersuites) and aim at minimizing resource usage for
+this target. They can be used as a basis for custom configurations.
+
+These files are complete replacements for the default crypto_config.h. To use one of
+them, you can pick one of the following methods:
+
+1. Replace the default file include/psa/crypto_config.h with the chosen one.
+
+2. Define TF_PSA_CRYPTO_CONFIG_FILE and adjust the include path accordingly.
+   For example, using cmake:
+
+    find . -iname '*cmake*' -not -name CMakeLists.txt -exec rm -rf {} +
+    CFLAGS="-I$PWD/configs -DCRYPTO_CONFIG_FILE='<foo.h>'" cmake .
+    make
+
+Note that the second method also works if you want to keep your custom
+configuration file outside the TF-PSA-Crypto tree.

configs/ext/README.md

@@ -1,19 +1,18 @@
 Summary
 -------
 
-The two files:
+The file:
 
 * crypto_config_profile_medium.h
-* tfm_mbedcrypto_config_profile_medium.h
 
 are copyright The Mbed TLS Contributors, and are distributed under the license normally
 used by Mbed TLS: a dual Apache 2.0 or GPLv2-or-later license.
 
 Background
 ----------
 
-The two files crypto_config_profile_medium.h and tfm_mbedcrypto_config_profile_medium.h
-are taken verbatim from the TF-M source code here:
+The two file crypto_config_profile_medium.h is taken verbatim from the TF-M
+source code here:
 
 https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/lib/ext/mbedcrypto/mbedcrypto_config