Update references to old Github organisation

Replace references to ARMmbed organisation with the new
org, Mbed-TLS, following project migration.

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/include/psa/crypto_config.h b/include/psa/crypto_config.h
index 6476e3c..d290971 100644
--- a/include/psa/crypto_config.h
+++ b/include/psa/crypto_config.h
@@ -97,7 +97,7 @@
 #define PSA_WANT_ECC_SECP_K1_192                1
 /*
  * SECP224K1 is buggy via the PSA API in Mbed TLS
- * (https://github.com/ARMmbed/mbedtls/issues/3541). Thus, do not enable it by
+ * (https://github.com/Mbed-TLS/mbedtls/issues/3541). Thus, do not enable it by
  * default.
  */
 //#define PSA_WANT_ECC_SECP_K1_224                1