spi/spi-pl022: Don't allocate more sg than required.

In routine configure_dma(), if transfer->len = PAGE_SIZE, then pages is one more
than required. While leads to one more sg getting allocated.

This is wrong. Correct this to allocate correct number of sg.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spi-pl022.c

@@ -1016,7 +1016,7 @@ static int configure_dma(struct pl022 *pl022)
 	dmaengine_slave_config(txchan, &tx_conf);
 
 	/* Create sglists for the transfers */
-	pages = (pl022->cur_transfer->len >> PAGE_SHIFT) + 1;
+	pages = DIV_ROUND_UP(pl022->cur_transfer->len, PAGE_SIZE);
 	dev_dbg(&pl022->adev->dev, "using %d pages for transfer\n", pages);
 
 	ret = sg_alloc_table(&pl022->sgt_rx, pages, GFP_ATOMIC);