Update gitignore to avoid tracking unwanted files

.gitignore updated to avoid tracking files generated after build. Following list
of files are added:
*.o
*.a
*.so
*.swp
*.patch
tags

Signed-off-by: Ajay Bhargav <ajay.bhargav@einfochips.com>

.gitignore

@@ -1,2 +1,8 @@
 .svn
 test
+*.o
+*.a
+*.so
+*.swp
+*.patch
+tags