soc/fsl/qbman: Add common routine for QBMan private allocations

The QBMan device uses several memory regions to manage frame
queues and buffers. Add a common routine for extracting and
initializing these reserved memory areas.

Signed-off-by: Roy Pledge <roy.pledge@nxp.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>