target-bin: allow tb-fw-config and hw-config to be part of uefi fip

With support for dynamic configuration now available, the tb-fw-config
and hw-config dtb blobs can be packaged into the uefi fip image.

Change-Id: I5dad50c1417f00297717c8430949f3153eff8408
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>