spi: designware: convert to livetree

Convert 'dw_spi_ofdata_to_platdata' to use 'dev_read_u32_default'
instead of 'fdtdec_get_int' and get rid of DECLARE_GLOBAL_DATA_PTR.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
index dadb6fa..7d58cfa 100644
--- a/drivers/spi/designware_spi.c
+++ b/drivers/spi/designware_spi.c
@@ -22,8 +22,6 @@
 #include <linux/iopoll.h>
 #include <asm/io.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 /* Register offsets */
 #define DW_SPI_CTRL0			0x00
 #define DW_SPI_CTRL1			0x04
@@ -155,14 +153,12 @@
 static int dw_spi_ofdata_to_platdata(struct udevice *bus)
 {
 	struct dw_spi_platdata *plat = bus->platdata;
-	const void *blob = gd->fdt_blob;
-	int node = dev_of_offset(bus);
 
 	plat->regs = (struct dw_spi *)devfdt_get_addr(bus);
 
 	/* Use 500KHz as a suitable default */
-	plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
-					500000);
+	plat->frequency = dev_read_u32_default(bus, "spi-max-frequency",
+					       500000);
 	debug("%s: regs=%p max-frequency=%d\n", __func__, plat->regs,
 	      plat->frequency);