drivers mtd: spi-nor: add Winbond W25Q20 variants

Winbond W25Q20BW devices are used in 4/5th generation Kindle ebook readers.
Add this spi-nor device and the similar W25Q20 devices to the list of known
devices.
Signed-off-by: Alexander Kurz <akurz@blala.de>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>

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

@@ -1131,6 +1131,9 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "w25x80", INFO(0xef3014, 0, 64 * 1024,  16, SECT_4K) },
 	{ "w25x16", INFO(0xef3015, 0, 64 * 1024,  32, SECT_4K) },
 	{ "w25x32", INFO(0xef3016, 0, 64 * 1024,  64, SECT_4K) },
+	{ "w25q20cl", INFO(0xef4012, 0, 64 * 1024,  4, SECT_4K) },
+	{ "w25q20bw", INFO(0xef5012, 0, 64 * 1024,  4, SECT_4K) },
+	{ "w25q20ew", INFO(0xef6012, 0, 64 * 1024,  4, SECT_4K) },
 	{ "w25q32", INFO(0xef4016, 0, 64 * 1024,  64, SECT_4K) },
 	{
 		"w25q32dw", INFO(0xef6016, 0, 64 * 1024,  64,