The correct testing of rollback relies to U-Boot behavior.
In Apertis we expect the U-Boot should to use rollback configuration
in case if boot counter is above the limit.

Unfortunately we break the normal boot of SabreLite and Renesas boards
in LAVA by running direct boot with `run bootcmd_mmc0` command.

This completely breaks the correct workflow for rollback since it relies
to command `altbootcmd` which is a part of Apertis distro boot
modification.
The U-Boot bootloader should to drop the warning if boot counter is
truggering the rollback:

  File System is consistent
  file found, deleting
  File System is consistent
  Warning: Bootlimit (3) exceeded. Using altbootcmd.

and proceed with the call of `altbootcmd` instead of `distro_bootcmd`.
But since we stop the boot and do a manual boot from mmc0, alternative
boot is never called.

To proceed with the correct behavior after breaking the boot process we
check the boot limit additionally and choose the proper boot variant.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>