fixup! CTR_DRBG: support set_entropy_len() before seed()

Remove a comment that documented a now-removed restriction.
diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 676b96e..05b4e95 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -301,11 +301,6 @@
  *
  * The default value is #MBEDTLS_CTR_DRBG_ENTROPY_LEN.
  *
- * \note                mbedtls_ctr_drbg_seed() always sets the entropy length
- *                      to #MBEDTLS_CTR_DRBG_ENTROPY_LEN, so this function
- *                      only has an effect when it is called after
- *                      mbedtls_ctr_drbg_seed().
- *
  * \note                The security strength of CTR_DRBG is bounded by the
  *                      entropy length. Thus:
  *                      - When using AES-256