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
diff --git a/runtime/include/smc-handler.h b/runtime/include/smc-handler.h
index 33557d4..222c5bf 100644
--- a/runtime/include/smc-handler.h
+++ b/runtime/include/smc-handler.h
@@ -109,6 +109,8 @@
 unsigned long smc_pdev_create(unsigned long pdev_ptr,
 			      unsigned long pdev_params_ptr);
 
+void smc_pdev_aux_count(unsigned long flags, struct smc_result *res);
+
 void smc_pdev_get_state(unsigned long pdev_ptr, struct smc_result *res);
 
 unsigned long smc_pdev_destroy(unsigned long pdev_ptr);