raw: remove unused variables from raw6_icmp_error()

saddr and daddr are set but not used.

Fixes: ba44f818

 ("raw: use more conventional iterators")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/r/20220622032303.159394-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>