msm: kgsl: Correctly return the context reset status

If fault recovery fails for a context mark the context as guilty
(and all the other contexts as innocent). The status is queried
by applications that support the EXT_robustness extension so they
can recover failed contexts.

If fault recovery is successful return no status because what the
user mode driver doesn't know won't hurt it.

CRs-fixed: 552328
Change-Id: Ic0dedbad50ad205e8a0d8e77815aaadce21ace40
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>