rusticl/device: fix custom device detection

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18809>

src/gallium/frontends/rusticl/core/device.rs

@@ -207,7 +207,7 @@ impl Device {
         // Max size of memory object allocation in bytes. The minimum value is
         // max(min(1024 × 1024 × 1024, 1/4th of CL_DEVICE_GLOBAL_MEM_SIZE), 32 × 1024 × 1024)
         // for devices that are not of type CL_DEVICE_TYPE_CUSTOM.
-        let mut limit = min(1024 * 1024 * 1024, self.global_mem_size());
+        let mut limit = min(1024 * 1024 * 1024, self.global_mem_size() / 4);
         limit = max(limit, 32 * 1024 * 1024);
         if self.max_mem_alloc() < limit {
             return true;