sf: Add ISSI IS25LP256 entry

Add entry for ISSI IS25LP256 part.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Jagan Teki <jagan@openedev.com>
diff --git a/drivers/mtd/spi/spi_flash_ids.c b/drivers/mtd/spi/spi_flash_ids.c
index 262d81e..b789219 100644
--- a/drivers/mtd/spi/spi_flash_ids.c
+++ b/drivers/mtd/spi/spi_flash_ids.c
@@ -71,6 +71,7 @@
 	{"is25lp032",	   INFO(0x9d6016, 0x0, 64 * 1024,    64, 0) },
 	{"is25lp064",	   INFO(0x9d6017, 0x0, 64 * 1024,   128, 0) },
 	{"is25lp128",	   INFO(0x9d6018, 0x0, 64 * 1024,   256, 0) },
+	{"is25lp256",	   INFO(0x9d6019, 0x0, 64 * 1024,   512, 0) },
 #endif
 #ifdef CONFIG_SPI_FLASH_MACRONIX	/* MACRONIX */
 	{"mx25l2006e",	   INFO(0xc22012, 0x0, 64 * 1024,     4, 0) },