Documentation/misc-devices/mei: Fix indentation of embedded code.

Some of the source code embedded in mei-client-bus.txt was indented
using spaces. This properly indents it with tabs and also removes a
single space that was placed in front of a closing curly brace.

Reviewed-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Julian Brost <linux-kernel@0x4a42.net>
Signed-off-by: Fabian Hofmann <fabian.hofmann@fau.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>