android: add .gitignore for empty dir and generated files

Signed-off-by: hmz007 <hmz007@gmail.com>

.gitignore

@@ -0,0 +1,36 @@
+#
+# NOTE! Don't add files that are generated in specific
+# subdirectories here. Add them in the ".gitignore" file
+# in that subdirectory instead.
+#
+# Normal rules
+#
+
+*.rej
+*.orig
+*~
+*.patch
+*.diff
+.DS_Store
+._*
+
+#
+# Top-level generic files
+#
+
+/out
+/rockdev
+/kernel/*.img
+/IMAGE
+
+#
+# Generated files
+#
+
+*.depend
+*.log
+/.bootstrap
+
+# cscope files
+cscope.*
+