linux-user: add fd_trans helper in do_recvfrom()

Fix passwd using netlink audit.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 491ab55..f9ce9d8 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -3316,6 +3316,9 @@
         ret = get_errno(safe_recvfrom(fd, host_msg, len, flags, NULL, 0));
     }
     if (!is_error(ret)) {
+        if (fd_trans_host_to_target_data(fd)) {
+            ret = fd_trans_host_to_target_data(fd)(host_msg, ret);
+        }
         if (target_addr) {
             host_to_target_sockaddr(target_addr, addr, addrlen);
             if (put_user_u32(addrlen, target_addrlen)) {