.gitignore: add backup files

Add *.orig and *~ backup files to gitignore.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

.gitignore

@@ -9,3 +9,5 @@
 /.config
 *.depend
 *.o
+*.orig
+*~