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>

include/u-boot/hash-checksum.h

@@ -21,7 +21,7 @@ struct image_region;
  * @region_count: Number of regions in the region array
  * @checksum: Buffer contanining the output hash
  *
- * @return 0 if OK, < 0 if error
+ * Return: 0 if OK, < 0 if error
  */
 int hash_calculate(const char *name,
 		   const struct image_region *region, int region_count,