Adding support for mips.

Support for mips cpu is added to all breakapad targets including unittests.

BUG=none
TEST=unittests

Review URL: https://breakpad.appspot.com/614002



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1212 4c0a9323-5329-0410-9bdc-e9ce6186880e