powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls

powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls

To issue ibm,get-indices, ibm,set-dynamic-indicator and
ibm,get-dynamic-sensor-state in the user space, the RMO buffer is
allocated for the work area which is restricted under system
lockdown. So instead of user space execution, the kernel will
provide /dev/papr-indices interface to execute these RTAS calls.

The user space assigns data in papr_indices_io_block struct
depends on the specific HCALL and passes to the following ioctls:

PAPR_INDICES_IOC_GET:		Use for ibm,get-indices. Returns a
				get-indices handle fd to read data.
PAPR_DYNAMIC_SENSOR_IOC_GET:	Use for  ibm,get-dynamic-sensor-state.
				Updates the sensor state in
				papr_indices_io_block.dynamic_param.state

PAPR_DYNAMIC_INDICATOR_IOC_SET:	Use for ibm,set-dynamic-indicator.
				Sets the new state for the input
				indicator.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Tested-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250416225743.596462-3-haren@linux.ibm.com