fdp: support scheme placement id (index) selection

fdp: support scheme placement id (index) selection

Add a new placement id selection method called scheme. It allows
users to assign a placement ID (index) depending on the offset range.
The strategy of the scheme is specified in the file by user and
is applicable using the option dp_scheme.

Signed-off-by: Hyunwoo Park <dshw.park@samsung.com>