gallium/hud: initialize query

Most of the drivers don't set up the maximum value in the query info. So
when later hud_pane_set_max_value() is invoked, we are using a rather
"random" number.

Turns out that in some 32bit cases, this random number is big enough
that `leftmost_digit` is 0 because DIV_ROUND_UP() overflows, aborting
with an assertion.

Fixes: c91cf7d7d2 ("gallium: implement a heads-up display module")
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12181>

src/gallium/auxiliary/hud/hud_driver_query.c

@@ -424,7 +424,7 @@ hud_driver_query_install(struct hud_batch_query_context **pbq,
                          struct hud_pane *pane, struct pipe_screen *screen,
                          const char *name)
 {
-   struct pipe_driver_query_info query;
+   struct pipe_driver_query_info query = { 0 };
    unsigned num_queries, i;
    boolean found = FALSE;