mtd: spi-nor: add support for s25fl128s

We need to store the six bytes ID for s25fl128s, since it shares the same
five bytes with s25fl129p1.

This patch adds a macro INFO6 which is used for the six bytes ID flash, and adds
a new item for the s25fl128s.

Signed-off-by: Huang Shijie <shijie.huang@intel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>