dataplacement: remove FDP_MAX_RUHS

dataplacement: remove FDP_MAX_RUHS

Earlier fio used to have different limits on the max number of data
placement ID indices which user can pass, and the max number of ruhs
which can be stored. As during initialization we now fetch all the ruhs
from the device and then allocate buffer for the requested ones, there
is no need for FDP_MAX_RUHS.

Add missing error message if incorrect placement ID index is specified.

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>