utils: Move core definitions from dt_table.h into dt_table_core.h

Move core data structures from dt_table.h into dt_table_core.h and
license it as BSD-3. This more permissive license will allow these core
definitions to be imported into more permissive bootloaders.

Bug: 394980221
Test: mmm system/libufdt

Change-Id: I33154dc2772660cc8c096a5744ae7a32df06871f
2 files changed