drivers: gic: Add multiple GIC redistributors regions support

For GIC multiple views feature support, all GIC Re-distributor's
GICR_TYPER.last will be set. Because configuration view-0 can
assign non-contiguous CPUs to views other than 0, in this case
the GIC Redistributors' registers won't seem contiguous.

So the GIC driver should cope with multiple sets of redistributors
like multi-chip scenarios. In this patch we add multiple GIC
redistributor regions support in GIC redistributor iteration.

For more information, refer to the Multi view subsection
in the GIC Technical Reference Manual.
For example:
https://developer.arm.com/documentation/101516/0400/Operation-of-GIC-700/Multi-view



Signed-off-by: Ziad Elhanafy <ziad.elhanafy@arm.com>