Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index df011ac..3b604c1 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -677,6 +677,7 @@
 	while (ret != rcvd) {
 		if (ret < 0)
 			exit_with_error(-ret);
+		complete_tx_l2fwd(xsk, fds);
 		if (xsk_ring_prod__needs_wakeup(&xsk->tx))
 			kick_tx(xsk);
 		ret = xsk_ring_prod__reserve(&xsk->tx, rcvd, &idx_tx);
@@ -782,5 +783,7 @@
 	else
 		l2fwd_all();
 
+	munmap(bufs, NUM_FRAMES * opt_xsk_frame_size);
+
 	return 0;
 }