LoongArch: mm: Avoid unnecessary page fault retires on shared memory types

Commit d92725256b ("mm: avoid unnecessary page fault retires on
shared memory types") modifies do_page_fault() to handle the VM_FAULT_
COMPLETED case, but forget to change for LoongArch, so fix it as other
architectures does.

Fixes: d92725256b ("mm: avoid unnecessary page fault retires on shared memory types")
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/mm/fault.c

@@ -216,6 +216,10 @@ good_area:
 		return;
 	}
 
+	/* The fault is fully completed (including releasing mmap lock) */
+	if (fault & VM_FAULT_COMPLETED)
+		return;
+
 	if (unlikely(fault & VM_FAULT_RETRY)) {
 		flags |= FAULT_FLAG_TRIED;