V4L/DVB (3300b): .gitignore should also ignore StGit generated dirs

StGit genreates patches-* when you run stg export command.
It makes no sense to show such directories as changes on git status.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/.gitignore b/.gitignore
index 3f8fb68..53e53f2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,5 @@
 include/linux/compile.h
 include/linux/version.h
 
+# stgit generated dirs
+patches-*