etnaviv: don't select TS modifier when not FAST_CLEAR capable

When presented with a list of modifiers to choose from we must never
pick a shared TS modifier if the local instance isn't FAST_CLEAR capable.

Fixes: c2b06e1a38 ("etnaviv: add support for sharing the TS buffer")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19751>

src/gallium/drivers/etnaviv/etnaviv_resource.c

@@ -519,6 +519,9 @@ select_best_modifier(const struct etna_screen * screen,
 
    best_modifier = base_modifier = priority_to_modifier[prio];
 
+   if (!VIV_FEATURE(screen, chipFeatures, FAST_CLEAR))
+      return best_modifier;
+
    /* Make a second pass to try and find the best TS modifier if any. */
    for (int i = 0; i < count; i++) {
       if ((modifiers[i] & ~VIVANTE_MOD_EXT_MASK) == base_modifier)