ANDROID: sched/fair: Also do misfit in overloaded groups

If we can classify the group as overloaded, that overrides
any classification as misfit but we may still have misfit
tasks present. Check the rq we're looking at to see if
this is the case.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
[Removed stray reference to rq_has_misfit]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Change-Id: Ida8eb66aa625e34de3fe2ee1b0dd8a78926273d8