KVM: PPC: Book3S PR: Transition to Suspended state when injecting interrupt

This patch simulates interrupt behavior per Power ISA while injecting
interrupt in PR KVM:
- When interrupt happens, transactional state should be suspended.

kvmppc_mmu_book3s_64_reset_msr() will be invoked when injecting an
interrupt. This patch performs this ISA logic in
kvmppc_mmu_book3s_64_reset_msr().

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>