etnaviv: allow sampler TS even if the resource is flushed

etnaviv: allow sampler TS even if the resource is flushed

As long as the TS is valid we can use the tile status to optimize the
sample fetch, even if the resource has been flushed for any reason.
Do the check for valid TS first when checking whether to enable sampler
TS to avoid all the other checks when TS isn't usable.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <cgmeiner@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19964>