Fix missing check for RSA key length on EE certs

- also adapt tests to use lesser requirement for compatibility with old
  testing material
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 72b02ff..294f36a 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -301,8 +301,8 @@
  *                 security profile.
  *
  * \note           The restrictions on keys (RSA minimum size, allowed curves
- *                 for ECDSA) only applys to (intermediate) CAs, not to the
- *                 end-entity certificate.
+ *                 for ECDSA) apply to all certificates: trusted root,
+ *                 intermediate CAs if any, and end entity certificate.
  *
  * \param crt      a certificate to be verified
  * \param trust_ca the trusted CA chain