firmware: ti_sci: Add support for RM core ops

TISCI provides support for getting the resources(IRQ, RING etc..)
assigned to a specific device. These resources can be handled by
the client and in turn sends TISCI cmd to configure the resources.

It is very important that client should keep track on usage of these
resources.

Add support for TISCI commands to get resource ranges.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>