Kernel: Some clang-tidy fixes in Bus/VirtIO

Author: https://github.com/Hendiadyoin1
Commit: 9be409585c
Pull-request: https://github.com/SerenityOS/serenity/pull/11188

Kernel/Bus/VirtIO/Queue.cpp

@@ -118,9 +118,9 @@ Optional<u16> Queue::take_free_slot()
         m_free_head = m_descriptors[descriptor_index].next;
         --m_free_buffers;
         return descriptor_index;
-    } else {
-        return {};
     }
+
+    return {};
 }
 
 bool Queue::should_notify() const