scripts: Add script to verify Android configurations

Android kernel trees include some config fragments of options that are
required to be set or unset.  This script compares a specific full
.config with these fragments to determine which configs are possibly
missing. An exemption file for the current msm-3.18 kernel tip is
included with this commit for perf and debug defconfigs. Errors related
to configs in these files are ignored.

Change-Id: I66e65dbc01081921f6695ec626594ec022a3f3c0
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Ian Maund <imaund@codeaurora.org>