The HSI documentation was moved into Documentation/driver-api/hsi.rst in
commit 5e995786 ("docs: split up serial-interfaces.rst"). Update the
corresponding file entry in MAINTAINERS.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>