feat(gic): add support for local chip addressing

This patch adds support for Local Chip Addressing (LCA). In a multi-chip
system, enablig LCA allows each GIC Distributor to maintain its own
version of routing table. This feature is activated when the
GICD_CFGID.LCA bit is set to 1.

The existing `gic600_multichip_data` data structure did not account for
the LCA feature. To support LCA:
- `rt_owner_base` is replaced by `base_addrs[]`. This is required
  because each GICD in the system needs to be configured independently,
  and their base addresses must be passed to the driver.
- `chip_addrs` is changed from 1D to 2D array to store the routing table
  for each chip's GICD. The entries in `chip_addrs` are configuration
  dependent, as the GIC specification does not enforce this.

On a multi-chip platform with chip count N where LCA is enabled by
default, the `gic600_multichip_data` structure should contain all copies
of the routing table (N*N entries). On platforms where LCA is not
supported, only the first sub-array with N entries is required. The
function signature of `gic600_multichip_init` remains unchanged, but if
the LCA feature is enabled, the driver will expect the routing table
configuration in the described format.

Change-Id: I8830c2cf90db6a0cae78e99914cd32c637284a2b
Signed-off-by: Jerry Wang <Jerry.Wang4@arm.com>