KVM: PPC: Book3S PR: Implement RFID TM behavior to suppress change from S0 to N0

According to ISA specification for RFID, in MSR TM disabled and TS
suspended state (S0), if the target MSR is TM disabled and TS state is
inactive (N0), rfid should suppress this update.

This patch makes the RFID emulation of PR KVM consistent with this.

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