doc: move smf section into os services

Move SMF frameowrk into OS Services.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/MAINTAINERS.yml b/MAINTAINERS.yml
index f97f967..2a3591c 100644
--- a/MAINTAINERS.yml
+++ b/MAINTAINERS.yml
@@ -1458,7 +1458,7 @@
     collaborators:
         - keith-zephyr
     files:
-        - doc/guides/smf/
+        - doc/services/smf/
         - include/smf.h
         - lib/smf/
         - tests/lib/smf/
diff --git a/doc/guides/index.rst b/doc/guides/index.rst
index 0b10206..6c4c07b 100644
--- a/doc/guides/index.rst
+++ b/doc/guides/index.rst
@@ -21,7 +21,6 @@
    platformio/index.rst
    portability/index.rst
    porting/index
-   smf/index.rst
    test/index
    tfm/index
    west/index
diff --git a/doc/services/index.rst b/doc/services/index.rst
index 6346934..2d1fae6 100644
--- a/doc/services/index.rst
+++ b/doc/services/index.rst
@@ -18,3 +18,4 @@
    pm/index.rst
    shell/index.rst
    settings/index.rst
+   smf/index.rst
diff --git a/doc/guides/smf/index.rst b/doc/services/smf/index.rst
similarity index 100%
rename from doc/guides/smf/index.rst
rename to doc/services/smf/index.rst