Reland "Remove gBn/sConstructorMap."

Use getBn/sConstructorMap() instead to avoid initialization
order problem.

This reverts commit c6ce6e50a77c08a17a28013599469b83d11049b0.

Reason for revert: internal devices are fixed.

Test: boots

Change-Id: Ia6f2bb09a6333abd87affb9c7c089d2ba512c7c9
Fixes: 69122224
4 files changed