Add patch command backup files to gitignore

To prevent similar mistakes as in commit cc6b3a3c ("vga: Handle line
feed"), add the backup files generated by 'patch' to gitignore.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

.gitignore

@@ -15,3 +15,6 @@ cscope.po.out
 
 *.pyc
 *.swp
+
+*.orig
+*.rej