feat(runtime/rmi): implement RMI_PDEV_AUX_COUNT

Implement RMI handler to get the number of auxiliary granules
required for a PDEV from PDEV flags.

Signed-off-by: Arunachalam Ganapathy <arunachalam.ganapathy@arm.com>
Change-Id: I30bb4acfe9454b959a1eabce6c7c234e9245dd38
5 files changed