Switch handshake->ecdh_bits to size_t and remove now useless cast & limit checks

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index e13b3d9..00f3989 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -630,7 +630,7 @@
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO) || defined(MBEDTLS_SSL_PROTO_TLS1_3)
     psa_key_type_t ecdh_psa_type;
-    uint16_t ecdh_bits;
+    size_t ecdh_bits;
     mbedtls_svc_key_id_t ecdh_psa_privkey;
     uint8_t ecdh_psa_shared_key;
     unsigned char ecdh_psa_peerkey[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];