V4L/DVB (8252): buf-dma-sg.c: avoid clearing memory twice

1) Remove a useless initialisation of 'i'

2) Avoid clearing the memory allocated twice (once in 'kcalloc', once
   in 'sg_init_table')

3) Remove a test that can never trigger.  The function returns NULL in
   such a case, so we know that at this point 'pages[0]' != NULL

Signed-off-by: Christophe Jaillet <jaillet.christophe@wanadoo.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/videobuf-dma-sg.c

@@ -80,17 +80,15 @@ struct scatterlist*
 videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
 {
 	struct scatterlist *sglist;
-	int i = 0;
+	int i;
 
 	if (NULL == pages[0])
 		return NULL;
-	sglist = kcalloc(nr_pages, sizeof(*sglist), GFP_KERNEL);
+	sglist = kmalloc(nr_pages * sizeof(*sglist), GFP_KERNEL);
 	if (NULL == sglist)
 		return NULL;
 	sg_init_table(sglist, nr_pages);
 
-	if (NULL == pages[0])
-		goto nopage;
 	if (PageHighMem(pages[0]))
 		/* DMA to highmem pages might not work */
 		goto highmem;