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: NAjay Bhargav <ajay.bhargav@einfochips.com>

.gitignore

 .svn
-test
\ No newline at end of file
+test
+*.o
+*.a
+*.so
+*.swp
+*.patch
+tags