MAINTAINERS: Add the CAN documentation file to the CAN section

MAINTAINERS: Add the CAN documentation file to the CAN section

Add can.rst to the corresponding section in MAINTAINERS, so that
the maintainers get CC:-ed on corresponding patches.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Vikram Garhwal <vikram.garhwal@amd.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Message-ID: <20231027060931.242491-1-thuth@redhat.com>
[PMD: Fixed typo in subject]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>