checkpatch: disable REPEATED_WORD

A new check in Linux checks for repeated words, which spews false
positives from text like:

* @param param the parameter
* @param device device instance

Signed-off-by: Peter A. Bigot <[email protected]>

Author: pabigot

.checkpatch.conf

@@ -19,4 +19,5 @@
 --ignore FILE_PATH_CHANGES
 --ignore SPDX_LICENSE_TAG
 --ignore C99_COMMENT_TOLERANCE
+--ignore REPEATED_WORD
 --exclude ext