This allows a board to modify initial_r0 if needed.
Also make default board behaviour functions always available, named as
mboot_get_reset_mode_default and mboot_state_change_default.
Signed-off-by: Damien George <damien@micropython.org>
All user interface (LED, button) code has been moved to ui.c, and the
interface to this code with the rest of the system now goes through calls
to mboot_state_change(). This state-change function can be overridden by a
board to fully customise the user interface behaviour.
Signed-off-by: Damien George <damien@micropython.org>
