gallium: Add PIPE_CAP_QUERY_TIMESTAMP_BITS

For those drivers that don't make full use of the 64 bits in
pipe_query_result.u64.

Applications will make use of it via GL_QUERY_COUNTER_BITS to handle
when the value rolls over.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10770>

src/gallium/include/pipe/p_defines.h

@@ -1001,6 +1001,7 @@ enum pipe_cap
    PIPE_CAP_DITHERING,
    PIPE_CAP_FBFETCH_ZS,
    PIPE_CAP_TIMELINE_SEMAPHORE_IMPORT,
+   PIPE_CAP_QUERY_TIMESTAMP_BITS,
 
    PIPE_CAP_LAST,
    /* XXX do not add caps after PIPE_CAP_LAST! */