mtd: pxa3xx_nand: introduce default timing to reduce read id times

We certainly don't need to send read id command times by times, since
we already know what the id is after the first read id...

So create a default timing which could ensure it would successfully read
id out all supported chip. Then follow the build-in table to reconfigure
the timing.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>