mtd: OneNAND: OMAP2: increase multiblock erase verify timeout

The current multiblock erase verify read timeout 100us is the maximum
for none-error case. If errors happen during multibock erase then
the specification recommends to run multiblock erase verify command
with maximum timeout 10ms (see specs. for KFM4G16Q2A and KFN8G16Q2A).

For the most common non-error case we wait 100us in udelay polling
loop. In case of timeout the interrupt mode is used to wait for the
command end.

Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>