Remove the use of global own_id from ffarpc_caller

Pass own_id as the parameter of ffa_caller_init to remove dependency
on own_id global variable. Change service locator to query the caller's
id via sp_discovery_own_id_get and pass it to the ffarpc_caller_init.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I1f654441f9a4f777335c111ac278aeeebd75bf30
diff --git a/deployments/sfs-demo/common/sfs_demo_sp.c b/deployments/sfs-demo/common/sfs_demo_sp.c
index a26c181..0b749b4 100644
--- a/deployments/sfs-demo/common/sfs_demo_sp.c
+++ b/deployments/sfs-demo/common/sfs_demo_sp.c
@@ -154,7 +154,7 @@
 	}
 	IMSG("Test SP ID: 0x%x", own_id);
 
-	caller = ffarpc_caller_init(&ffa_caller);
+	caller = ffarpc_caller_init(&ffa_caller, own_id);
 	sp_id_cnt = ffarpc_caller_discover(its_uuid, sp_ids, 3);
 
 	if (sp_id_cnt == 0) {