net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_table_info()

xt_alloc_table_info() basically opencodes kvmalloc() so use the library
function instead.

Link: http://lkml.kernel.org/r/20170531155145.17111-4-mhocko@kernel.orgSigned-off-by: Michal Hocko <mhocko@suse.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/netfilter/x_tables.c

@@ -1003,14 +1003,10 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
 	if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
 		return NULL;
 
-	if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
-		info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
-	if (!info) {
-		info = __vmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
-				 PAGE_KERNEL);
-		if (!info)
-			return NULL;
-	}
+	info = kvmalloc(sz, GFP_KERNEL);
+	if (!info)
+		return NULL;
+
 	memset(info, 0, sizeof(*info));
 	info->size = size;
 	return info;