selftests: hsr: add missing config for CONFIG_BRIDGE

hsr_redbox.sh test need to create bridge for testing. Add the missing
config CONFIG_BRIDGE in config file.

Fixes: eafbf0574e05 ("test: hsr: Extend the hsr_redbox.sh to have more SAN devices connected")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Tested-by: Simon Horman <horms@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: Add a basic HSR test.

This test adds a basic HSRv0 network with 3 nodes. In its current shape
it sends and forwards packets, announcements and so merges nodes based
on MAC A/B information.
It is able to detect duplicate packets and packetloss should any occur.

Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>