rust: pci: impl Send + Sync for pci::Device

Commit 7b948a2 ("rust: pci: fix unrestricted &mut pci::Device")
changed the definition of pci::Device and discarded the implicitly
derived Send and Sync traits.

This isn't required by upstream code yet, and hence did not cause any
issues. However, it is relied on by upcoming drivers, hence add it back
in.

Signed-off-by: Danilo Krummrich <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Danilo Krummrich

rust/kernel/pci.rs

@@ -465,3 +465,10 @@ impl AsRef<device::Device> for Device {
         unsafe { device::Device::as_ref(dev) }
     }
 }
+
+// SAFETY: A `Device` is always reference-counted and can be released from any thread.
+unsafe impl Send for Device {}
+
+// SAFETY: `Device` can be shared among threads because all methods of `Device`
+// (i.e. `Device<Normal>) are thread safe.
+unsafe impl Sync for Device {}