KVM: Remove unused kvm_device_{get,put}() declarations

Commit 07f0a7b ("kvm: destroy emulated devices on VM exit") removed the
functions but not these declarations.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20230814140339.47732-1-yuehaibing@huawei.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

include/linux/kvm_host.h

@@ -2152,8 +2152,6 @@ struct kvm_device_ops {
 	int (*mmap)(struct kvm_device *dev, struct vm_area_struct *vma);
 };
 
-void kvm_device_get(struct kvm_device *dev);
-void kvm_device_put(struct kvm_device *dev);
 struct kvm_device *kvm_device_from_filp(struct file *filp);
 int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type);
 void kvm_unregister_device_ops(u32 type);