renderonly: fix dumb BO allocation for non 32bpp formats

Take into account the resource format, instead of applying a hardcoded
32bpp. This not only over-allocates 16bpp formats, but also results in
a wrong stride being filled into the handle.

Fixes: 848b49b288 ("gallium: add renderonly library")
CC: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Daniel Stone <daniels@collabora.com>

src/gallium/auxiliary/renderonly/renderonly.c

@@ -33,6 +33,7 @@
 
 #include "state_tracker/drm_driver.h"
 #include "pipe/p_screen.h"
+#include "util/u_format.h"
 #include "util/u_inlines.h"
 #include "util/u_memory.h"
 
@@ -73,7 +74,7 @@ renderonly_create_kms_dumb_buffer_for_resource(struct pipe_resource *rsc,
    struct drm_mode_create_dumb create_dumb = {
       .width = rsc->width0,
       .height = rsc->height0,
-      .bpp = 32,
+      .bpp = util_format_get_blocksizebits(rsc->format),
    };
    struct drm_mode_destroy_dumb destroy_dumb = { };