docs/system: Add vhost-user-input documentation

This adds basic documentation for vhost-user-input.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Message-Id: <20231120043721.50555-3-leo.yan@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240104210945.1223134-10-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index aff5342..66c9e81 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2289,6 +2289,7 @@
 virtio-input
 M: Gerd Hoffmann <kraxel@redhat.com>
 S: Odd Fixes
+F: docs/system/devices/vhost-user-input.rst
 F: hw/input/vhost-user-input.c
 F: hw/input/virtio-input*.c
 F: include/hw/virtio/virtio-input.h