sf: spansion: Update the name for S25FL256S flash

As the per the ID tabl the flash is under Uniform 64-kB sector
architecture, hence updated with proper name.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
diff --git a/drivers/mtd/spi/spansion.c b/drivers/mtd/spi/spansion.c
index 307b852..2218e2f 100644
--- a/drivers/mtd/spi/spansion.c
+++ b/drivers/mtd/spi/spansion.c
@@ -108,7 +108,7 @@
 		.idcode2 = 0x4d01,
 		.pages_per_sector = 256,
 		.nr_sectors = 512,
-		.name = "S25FL256S",
+		.name = "S25FL256S_64K",
 	},
 };