of/spi: call of_register_spi_devices() from spi core code

Move of_register_spi_devices() call from drivers to
spi_register_master(). Also change the function to use
the struct device_node pointer from master spi device
instead of passing it as function argument.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
index 1b47363..80f2db5 100644
--- a/drivers/spi/xilinx_spi.c
+++ b/drivers/spi/xilinx_spi.c
@@ -390,6 +390,9 @@
 
 	master->bus_num = bus_num;
 	master->num_chipselect = pdata->num_chipselect;
+#ifdef CONFIG_OF
+	master->dev.of_node = dev->of_node;
+#endif
 
 	xspi->mem = *mem;
 	xspi->irq = irq;