rusticl/screen: fix driver_uuid on non x86

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9116
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23284>

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

@@ -11,7 +11,7 @@ use mesa_rust_util::string::*;
 use std::convert::TryInto;
 use std::ffi::CStr;
 use std::mem::size_of;
-use std::os::raw::c_char;
+use std::os::raw::c_schar;
 use std::os::raw::c_uchar;
 use std::os::raw::c_void;
 use std::ptr;
@@ -267,7 +267,7 @@ impl PipeScreen {
         unsafe { *self.ldev.ldev }.type_
     }
 
-    pub fn driver_uuid(&self) -> Option<[c_char; UUID_SIZE]> {
+    pub fn driver_uuid(&self) -> Option<[c_schar; UUID_SIZE]> {
         let mut uuid = [0; UUID_SIZE];
         let ptr = uuid.as_mut_ptr();
         unsafe {