sf: winbond: fix page_size

Commit a4ed3b6 "sf: inline data constants" modified winbond.c's page_size
from 256 to 4096. This prevents either/both of "sf write" writing the
correct data, or "sf read" from reading the correct data back.

This allows U-Boot running on Compulab Tegra to upgrade itself.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/drivers/mtd/spi/winbond.c b/drivers/mtd/spi/winbond.c
index 6d9b3af..f6aab3d 100644
--- a/drivers/mtd/spi/winbond.c
+++ b/drivers/mtd/spi/winbond.c
@@ -99,7 +99,7 @@
 	flash->write = spi_flash_cmd_write_multi;
 	flash->erase = spi_flash_cmd_erase;
 	flash->read = spi_flash_cmd_read_fast;
-	flash->page_size = 4096;
+	flash->page_size = 256;
 	flash->sector_size = 4096;
 	flash->size = 4096 * 16 * params->nr_blocks;