Revert "arch: arm: use dt and UCLASS_SYSCON to get gic lpi details"

Stop using the device tree as a source for ad-hoc information.

This reverts commit 2ae7adc6.

Signed-off-by: Michael Walle <michael@walle.cc>
[trini: Also make board/broadcom/bcmns3/ns3.c fail clearly now]
Signed-off-by: Tom Rini <trini@konsulko.com>