net: lantiq_xrx200: restore buffer if memory allocation failed

net: lantiq_xrx200: restore buffer if memory allocation failed

[ Upstream commit c9c3b1775f80fa21f5bff874027d2ccb10f5d90c ]

In a situation where memory allocation fails, an invalid buffer address
is stored. When this descriptor is used again, the system panics in the
build_skb() function when accessing memory.

Fixes: 7ea6cd16f159 ("lantiq: net: fix duplicated skb in rx descriptor ring")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>