netfilter: bitwise: improve error goto labels

[ Upstream commit 00bd4352

 ]

Replace two labels (`err1` and `err2`) with more informative ones.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>