doc: replace @return by Return:

Sphinx expects Return: and not @return to indicate a return value.

find . -name '*.c' -exec \
sed -i 's/^\(\s\)\*\(\s*\)@return\(\s\)/\1*\2Return:\3/' {} \;

find . -name '*.h' -exec \
sed -i 's/^\(\s\)\*\(\s*\)@return\(\s\)/\1*\2Return:\3/' {} \;

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/cmd/pinmux.c b/cmd/pinmux.c
index 2d23357..f17cf41 100644
--- a/cmd/pinmux.c
+++ b/cmd/pinmux.c
@@ -47,7 +47,7 @@
  * @param dev		pinctrl device
  * @param name		NULL to display all the pins
  *			or name of the pin to display
- * @return 0 on success, non-0 on error
+ * Return: 0 on success, non-0 on error
  */
 static int show_pinmux(struct udevice *dev, char *name)
 {