xtables: Don't pass full invflags to add_compat()

xtables: Don't pass full invflags to add_compat()

The function expects a boolean, not a bitfield. This bug caused
inversion in another match to carry over to protocol match by accident.
The supplied testcase contains rules which then fail because they
contain matches requiring that protocol.

Fixes: 4ef77b6d1b52e ("xtables: fix missing protocol and invflags")
Fixes: 4143a08819a07 ("ebtables-compat: add nft rule compat information to bridge rules")
Signed-off-by: Phil Sutter <phil@nwl.cc>