clk: sifive: Fix -Wint-to-pointer-cast warning

dev_read_addr() returns a value of type fdt_addr_t which is a 64-bit
address and pd->va is a pointer. In a 32-bit build, this causes the
following warning seen when building sifive-prci.c:

  warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

Change to use dev_read_addr_ptr().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/drivers/clk/sifive/sifive-prci.c b/drivers/clk/sifive/sifive-prci.c
index cd1acb9..52ae268 100644
--- a/drivers/clk/sifive/sifive-prci.c
+++ b/drivers/clk/sifive/sifive-prci.c
@@ -653,9 +653,9 @@
 	struct prci_clk_desc *data =
 		(struct prci_clk_desc *)dev_get_driver_data(dev);
 
-	pd->va = (void *)dev_read_addr(dev);
-	if (IS_ERR(pd->va))
-		return PTR_ERR(pd->va);
+	pd->va = dev_read_addr_ptr(dev);
+	if (!pd->va)
+		return -EINVAL;
 
 	err = clk_get_by_index(dev, 0, &pd->parent_hfclk);
 	if (err)