Add support for new LAW registers in QorIQ SoCs.

QorIQ SoCs (e5500 core, P5 family) have 2 BARs for local access windows, while
MPC85XX, and P1/P2 families use only a single BAR register.

This also adds the QORIQ_DPAA option, mutually exclusive to MPC85XX, to handle
this difference.

Obtained from: Semihalf
Sponsored by: Alex Perez/Inertial Computing