ssl: fix getting group id in ssl_check_key_curve()

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index d2143ac..b4719d6 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -676,7 +676,11 @@
                                uint16_t *curves_tls_id)
 {
     uint16_t *curr_tls_id = curves_tls_id;
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+    mbedtls_ecp_group_id grp_id = mbedtls_ecc_group_of_psa(pk->ec_family, pk->ec_bits, 0);
+#else
     mbedtls_ecp_group_id grp_id = mbedtls_pk_ec_ro(*pk)->grp.id;
+#endif
     mbedtls_ecp_group_id curr_grp_id;
 
     while (*curr_tls_id != 0) {