MAINTAINERS: rectify file entry in BONDING DRIVER

Commit c078290a

 ("selftests: include bonding tests into the kselftest
infra") adds the bonding tests in the directory:

  tools/testing/selftests/drivers/net/bonding/

The file entry in MAINTAINERS for the BONDING DRIVER however refers to:

  tools/testing/selftests/net/bonding/

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken file pattern.

Repair this file entry in BONDING DRIVER.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Jonathan Toppins <jtoppins@redhat.com>
Link: https://lore.kernel.org/r/20220824072945.28606-1-lukas.bulwahn@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>