[PATCH v1 1/3] mtd: physmap: add dual die entry in devicetree binding

[Bean Huo]

Boris,
thanks for the review.

>> + - dual-die-stack: boolean to enable support for the devices with the
>> +   two dies in stack.

>How about making that more future proof and adding a property that
>directly contains the number of dies (num-dies)?

Exactly, I also thought here should add a property, through which it can be compatible
with all kinds of PNOR for the future more dies stacked device.
But currently, it doesn't exist  PNOR device with more than two dies, and we
have no idea about 4/6 dies stacked device operation sequence. so I simply add a boolean
entry and try to only enable dual-die stacked PNOR firstly.

Maybe I can try to do that in next version patch. the software implementation is so flexible.

>>
>>  For JEDEC compatible devices, the following additional properties
>>  are defined: