network/address: do not configure with IFA_F_TENTATIVE

Follow-up for 0a0c2672db.

After the commit, remembered Address objects by Link are always given by
kernel. Hence, it is not necessary to set the flag, as it is always
ignored by the kernel, and the kernel set the flag on notification if it
is necessary.

src/network/networkd-address.c

@@ -1600,9 +1600,6 @@ int link_request_address(
                 if (r < 0)
                         return log_link_warning_errno(link, r, "Failed to acquire an address from pool: %m");
 
-                /* Consider address tentative until we get the real flags from the kernel */
-                tmp->flags |= IFA_F_TENTATIVE;
-
         } else {
                 r = address_dup(address, &tmp);
                 if (r < 0)