arm: imx: hab: Add hab_failsafe console command

arm: imx: hab: Add hab_failsafe console command

hab_failsafe when called puts the part into BootROM recovery mode.
This will allow u-boot scripts to script the dropping down into recovery
mode.

=> hab_failsafe

Shows the i.MX7 appear as "hiddev0,hidraw5: USB HID v1.10 Device [Freescale
SemiConductor Inc  SP Blank ULT1] " in a Linux dmesg thus allowing download
of a new image via the BootROM USB download protocol routine.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Sven Ebenfeld <sven.ebenfeld@gmail.com>
Cc: George McCollister <george.mccollister@gmail.com>
Cc: Breno Matheus Lima <brenomatheus@gmail.com>
Tested-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>