Introduce halt()

It's a portable and generic way to halt the system.
Useful when waiting for the platform to reset.

Change-Id: Ie07f3333d294a4d3e982cbc2ab9014c94b39fce0
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: http://review.coreboot.org/7605
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
3 files changed