add further OF support to plat_nand driver

chip-delay, bbt-use-flash and width

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
first step to plumbing in NAND support for TS-7800 DT platform

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
add support to read number of chips from DT for plat_nand

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
got the NAND working...it seems

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
helps if I ask plat-nand to use ofpart

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
and now to grow a pair and remove the read-only flags from the
NAND partition table

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
plat_nand: nr_chips can be more than 1, just not less than

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
added plat-nand DT bindings documentation

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
fix up so that 'ts' is used as vendor identifier

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>