mac80211: fix unaligned access in mesh table hash function

[ Upstream commit 40586e3fc400c00c11151804dcdc93f8c831c808 ]

The pointer to the last four bytes of the address is not guaranteed to be
aligned, so we need to use __get_unaligned_cpu32 here

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>