altera_spi: change ioremap to map_physmem

Change ioremap() to map_physmem(), as it is more used in u-boot.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/spi/altera_spi.c b/drivers/spi/altera_spi.c
index 3e09592..eb1ba27 100644
--- a/drivers/spi/altera_spi.c
+++ b/drivers/spi/altera_spi.c
@@ -174,8 +174,9 @@
 {
 	struct altera_spi_platdata *plat = dev_get_platdata(bus);
 
-	plat->regs = ioremap(dev_get_addr(bus),
-		sizeof(struct altera_spi_regs));
+	plat->regs = map_physmem(dev_get_addr(bus),
+				 sizeof(struct altera_spi_regs),
+				 MAP_NOCACHE);
 
 	return 0;
 }