VENDOR: ARM: rockchip: rk3036: save boot mode for "reboot fastboot"

When try to reboot with "fastboot" cmd, save boot mode in
grf_os_reg0, then the loader could check it and enter fastboot
mode.

Bug: 25923642
Patchset: rk3036 evb bring up

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Change-Id: Id598852614e2ed03a03c58dc0cf2f17cc164308c
1 file changed