When UEFI is used instead of BIOS, the location of `grub.cfg` is
different.
However, DIB only handles /boot/grub2/grub.cfg, so we copy the
same grub.cfg to the EFI System Partition (ESP) explicitly.
While at it, add ttyAMA0 (the default serial console on aarch64).
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
Change-Id: I2da27559fce2cabc129f18cea743919ecd09ef4e