kbuild: delete *.pyc files by "make distclean"

The tools "buildman" and "patman" are written in Python.
When we run them, "*.pyc" files are created under
tools/buildman, tools/patman directories.

They should be cleaned up by "make distclean".

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
Acked-by: Simon Glass <sjg@chromium.org>

Makefile

@@ -1228,7 +1228,7 @@ distclean: mrproper
 	@find $(srctree) $(RCS_FIND_IGNORE) \
 		\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
 		-o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
-		-o -name '.*.rej' \
+		-o -name '.*.rej' -o -name '*.pyc' \
 		-o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
 		-type f -print | xargs rm -f