powerpc/64s/slb: Make preload_add return type as void

We dropped preload_new_slb_context() & slb_setup_new_exec() in a
previous patch. That means we don't really need preload_add() return
type anymore. So let's make its return type as void.

Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/88b07223e93b0fc56c1119f6889b7d9c83e20109.1761834163.git.ritesh.list@gmail.com

Author: riteshharjani

arch/powerpc/mm/book3s64/slb.c

@@ -294,7 +294,7 @@ static bool preload_hit(struct thread_info *ti, unsigned long esid)
 	return false;
 }
 
-static bool preload_add(struct thread_info *ti, unsigned long ea)
+static void preload_add(struct thread_info *ti, unsigned long ea)
 {
 	unsigned char idx;
 	unsigned long esid;
@@ -308,16 +308,14 @@ static bool preload_add(struct thread_info *ti, unsigned long ea)
 	esid = ea >> SID_SHIFT;
 
 	if (preload_hit(ti, esid))
-		return false;
+		return;
 
 	idx = (ti->slb_preload_tail + ti->slb_preload_nr) % SLB_PRELOAD_NR;
 	ti->slb_preload_esid[idx] = esid;
 	if (ti->slb_preload_nr == SLB_PRELOAD_NR)
 		ti->slb_preload_tail = (ti->slb_preload_tail + 1) % SLB_PRELOAD_NR;
 	else
 		ti->slb_preload_nr++;
-
-	return true;
 }
 
 static void preload_age(struct thread_info *ti)