mtd: spi-nor: Add 4B_OPCODES flag to w25q256

The w25q256 supports 4-byte opcodes so lets add the flag.
Tested on OpenWrt under 4.19.82 kernel on 8devices Habanero.
Signed-off-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -2628,7 +2628,9 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
 	{ "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
 	{ "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
-	{ "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+	{ "w25q256", INFO(0xef4019, 0, 64 * 1024, 512,
+			  SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			  SPI_NOR_4B_OPCODES) },
 	{ "w25q256jvm", INFO(0xef7019, 0, 64 * 1024, 512,
 			     SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
 	{ "w25q256jw", INFO(0xef6019, 0, 64 * 1024, 512,