doc: include file-system API into HTML docs

Add include/fs.h to the API documentation.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/doc/api/fs.rst b/doc/api/fs.rst
new file mode 100644
index 0000000..38c8b0d
--- /dev/null
+++ b/doc/api/fs.rst
@@ -0,0 +1,7 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+File system API
+===============
+
+.. kernel-doc:: include/fs.h
+   :internal:
diff --git a/doc/api/index.rst b/doc/api/index.rst
index 9f7f23f..a108718 100644
--- a/doc/api/index.rst
+++ b/doc/api/index.rst
@@ -12,6 +12,7 @@
    dm
    efi
    event
+   fs
    getopt
    interrupt
    led