rusticl: allow packagers to enable radeonsi by default

Radeonsi hasn't yet passed conformance, so it's not part of the auto set
at this point in time. But this will allow distribution to enable it if
they feel comfortable enough, or to disable it again, if it causes too
many problems.

Acked-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34621>

meson.options

@@ -156,7 +156,7 @@ option(
 option(
   'gallium-rusticl-enable-drivers',
   type : 'array',
-  value : ['auto', 'asahi'],
+  value : ['auto', 'asahi', 'radeonsi'],
   description : 'List of gallium drivers for which rusticl will be enabled ' +
                 'by default',
 )

src/gallium/frontends/rusticl/mesa/pipe/device.rs

@@ -64,6 +64,8 @@ fn get_enabled_devs() -> HashMap<String, u32> {
     let default_devs: &[&str] = &[
         #[cfg(any(rusticl_enable_asahi, rusticl_enable_auto))]
         "asahi",
+        #[cfg(any(rusticl_enable_radeonsi))]
+        "radeonsi",
     ];
 
     // I wished we could use different iterators, but that's not really working out.