mtd: pxa3xx_nand: fix some compile issues on non-ARM arches

Using readsl() result in a build error on i386. Fix this by using
ioread32_rep() instead, to allow compile testing the pxa3xx nand driver
on other architectures later.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -532,7 +532,7 @@ static void drain_fifo(struct pxa3xx_nand_info *info, void *data, int len)
 		 * the polling on the last read.
 		 */
 		while (len > 8) {
-			readsl(info->mmio_base + NDDB, data, 8);
+			ioread32_rep(info->mmio_base + NDDB, data, 8);
 
 			ret = readl_relaxed_poll_timeout(info->mmio_base + NDSR, val,
 							 val & NDSR_RDDREQ, 1000, 5000);
@@ -547,7 +547,7 @@ static void drain_fifo(struct pxa3xx_nand_info *info, void *data, int len)
 		}
 	}
 
-	readsl(info->mmio_base + NDDB, data, len);
+	ioread32_rep(info->mmio_base + NDDB, data, len);
 }
 
 static void handle_data_pio(struct pxa3xx_nand_info *info)