[flashrom] [Patch] Winbond W25Q64 support

[David Hendricks]

This patch adds support for the W25Q64. It's similar, but has its own
datasheet [Linkhttp://www.winbond.com.tw/hq/enu/ProductAndSales/ProductLines/FlashMemory/SerialFlash/W25Q64BV.htm],
although it's mentioned in the W25Q{80,16,32} datasheet once.

Anyway, I happen to have one and was able to successfully read, erase, and
write to it using an NM10 based device. I was only able to successfully
erase with D8h block erase and C7h chip erase commands, but other than that
it seemed to work great.

Patch attached.

Signed-off by: David Hendricks ([e-mail])