powerpc/powernv: Enable cpuidle state detection for POWER11

powerpc/powernv: Enable cpuidle state detection for POWER11

Extend cpuidle state detection to POWER11 by updating the PVR check.
This ensures POWER11 correctly recognizes supported stop states,
similar to POWER9 and POWER10.

Without Patch: (Power11 - PowerNV systems)

CPUidle driver: powernv_idle
CPUidle governor: menu
analyzing CPU 927:

Number of idle states: 1
Available idle states: snooze
snooze:
Flags/Description: snooze
Latency: 0
Usage: 251631
Duration: 207497715900

--
With Patch: (Power11 - PowerNV systems)

CPUidle driver: powernv_idle
CPUidle governor: menu
analyzing CPU 959:

Number of idle states: 4
Available idle states: snooze stop0_lite stop0 stop3
snooze:
Flags/Description: snooze
Latency: 0
Usage: 2
Duration: 33
stop0_lite:
Flags/Description: stop0_lite
Latency: 1
Usage: 1
Duration: 52
stop0:
Flags/Description: stop0
Latency: 10
Usage: 13
Duration: 1920
stop3:
Flags/Description: stop3
Latency: 45
Usage: 381
Duration: 21638478

Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Reviewed-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250908085123.216780-1-aboorvad@linux.ibm.com