Due to a misplaced parenthesis, the expression
(unlikely(offset) < 0),
which expands to
(__builtin_expect(!!(offset), 0) < 0),
never evaluates to true. Therefore, when sending packets with
PF_PACKET/SOCK_DGRAM, packet_snd() does not abort as intended
if the creation of the layer 2 header fails.
Spotted by Coverity - CID 1259975 ("Operands don't affect result").
Fixes: 9c7077622dd9 ("packet: make packet_snd fail on len smaller than l2 header")
Signed-off-by: Christoph Jaeger <cj@xxxxxxxxx>