Mark the Sansa c200v2 series of players as stable

These were originally held back as unstable due to bugs in rockbox's
audio buffering that only occuried on very low memory targets.  The
c200v2 is the lowest memory target we have.  Various improvements
to our buffering system seem to have fully corrected these problems.

Change-Id: I4404fe9b85c037904aea4b720e5a1fcb266f3d18

tools/builds.pm

@@ -223,7 +223,7 @@ $releasenotes="/wiki/ReleaseNotes310";
     },
     'sansac200v2' => {
         name => 'SanDisk Sansa c200 v2',
-        status => 2,
+        status => 3,
         icon => 'sansac200',
     },
     'sansaclip' => {