Add max device width parameter for NOR devices

Add max device width parameter for NOR devices

For handling CFI and device ID reads, we need to not only know the
width that a NOR flash device is configured for, but also its maximum
width.  The maximum width addressing mode is used for multi-width
parts no matter which width they are configured for.  The most common
case is x16 parts that also support x8 mode.  When configured for x8
operation these devices respond to CFI and device ID requests differently
than native x8 NOR parts.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
Message-id: 1386279359-32286-6-git-send-email-roy.franz@linaro.org
[PMM: Added comment explaining the semantics of width vs device-width
 vs max-device-width]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>