KVM: PPC: Book3S HV Nested: save_hv_return_state does not require trap argument

vcpu is already anargument so vcpu->arch.trap can be used directly.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210811160134.904987-9-npiggin@gmail.com