target-mips: Clean up switch fall through after commit fecd264 Commit fecd264 added a number of fall-throughs, but neglected to properly document them as intentional. Commit d922445 cleaned that up for many, but not all cases. Take care of the remaining ones. Spotted by Coverity. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>