sf: winbond: Add support for W25Q256

Add support for Winbond W25Q256 SPI flash.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
diff --git a/drivers/mtd/spi/winbond.c b/drivers/mtd/spi/winbond.c
index 2716209..3b39ba7 100644
--- a/drivers/mtd/spi/winbond.c
+++ b/drivers/mtd/spi/winbond.c
@@ -63,6 +63,11 @@
 		.name			= "W25Q128",
 	},
 	{
+		.id			= 0x4019,
+		.nr_blocks		= 512,
+		.name			= "W25Q256",
+	},
+	{
 		.id			= 0x5014,
 		.nr_blocks		= 128,
 		.name			= "W25Q80",