mm: sharepool: delete redundant check in __sp_remap_get_pfn

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5QETC
CVE: NA

--------------------------------

sp_make_share_k2u only supports vmalloc address now. Therefore, delete a
backup handle case.
Signed-off-by: NGuo Mengqi <guomengqi3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

mm/share_pool.c

@@ -2860,11 +2860,11 @@ static int is_vmap_hugepage(unsigned long addr)
 
 static unsigned long __sp_remap_get_pfn(unsigned long kva)
 {
-	unsigned long pfn;
+	unsigned long pfn = -EINVAL;
+
+	/* sp_make_share_k2u only support vmalloc address */
 	if (is_vmalloc_addr((void *)kva))
 		pfn = vmalloc_to_pfn((void *)kva);
-	else
-		pfn = virt_to_pfn(kva);
 
 	return pfn;
 }