pk_internal: small renaming for mbedtls_pk_get_group_id()

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index b007e5c..54e1cd4 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -664,7 +664,7 @@
                                uint16_t *curves_tls_id)
 {
     uint16_t *curr_tls_id = curves_tls_id;
-    mbedtls_ecp_group_id grp_id = mbedtls_pk_get_group_id(pk);
+    mbedtls_ecp_group_id grp_id = mbedtls_pk_get_ec_group_id(pk);
     mbedtls_ecp_group_id curr_grp_id;
 
     while (*curr_tls_id != 0) {
@@ -2651,7 +2651,7 @@
         case MBEDTLS_PK_ECKEY_DH:
         case MBEDTLS_PK_ECDSA:
             key = mbedtls_pk_ec_rw(*pk);
-            grp_id = mbedtls_pk_get_group_id(pk);
+            grp_id = mbedtls_pk_get_ec_group_id(pk);
             if (grp_id == MBEDTLS_ECP_DP_NONE) {
                 return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
             }