ivy: Add a possiblity for mainboard early init.

This is needed for stout EC init.

Change-Id: I5c73499c17763229840152a473a2d820802ee2f6
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: https://review.coreboot.org/13535
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
13 files changed