ARC: HSDK: anounce state of BIM switch

Anounce state of BIM switch which defines if U-boot is loaded
and started by preloader or not.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>