Update s25fl256 flash device id, cypress now. (#285)

* Updated s25fl256 flash device id, cypress now.

* Put the old entry back to support older board.

Author: kenzhang82

src/flash/nor/spi.c

@@ -54,6 +54,7 @@ const struct flash_device flash_devices[] = {
 	FLASH_ID("sp s25fl164k",        0xd8, 0xc7, 0x00174001, 0x100, 0x10000, 0x800000),
 	FLASH_ID("sp s25fl128",         0xd8, 0xc7, 0x00182001, 0x100, 0x10000, 0x1000000),
 	FLASH_ID("sp s25fl256",         0xd8, 0xc7, 0x00190201, 0x100, 0x10000, 0x2000000),
+	FLASH_ID("cy s25fl256",         0xd8, 0xc7, 0x00196001, 0x100, 0x10000, 0x2000000),
 	FLASH_ID("atmel 25f512",        0x52, 0xc7, 0x0065001f, 0x80,  0x8000,  0x10000),
 	FLASH_ID("atmel 25f1024",       0x52, 0x62, 0x0060001f, 0x100, 0x8000,  0x20000),
 	FLASH_ID("atmel 25f2048",       0x52, 0x62, 0x0063001f, 0x100, 0x10000, 0x40000),