cmd: bcb: introduce 'ab_dump' command to print BCB block content

cmd: bcb: introduce 'ab_dump' command to print BCB block content

It's really helpful to have the ability to dump BCB block for debugging
A/B logic on the board supported this partition schema.

Command 'bcb ab_dump' prints all fields of bootloader_control struct
including slot_metadata for all presented slots.

Output example:
=====
> board# bcb ab_dump ubi 0#misc
> Read 512 bytes from volume misc to 000000000bf07580
> Read 512 bytes from volume misc to 000000000bf42f40
> Bootloader Control:       [misc]
> Active Slot:              _a
> Magic Number:             0x42414342
> Version:                  1
> Number of Slots:          2
> Recovery Tries Remaining: 0
> CRC:                      0x2c8b50bc (Valid)
>
> Slot[0] Metadata:
> 	- Priority:         15
> 	- Tries Remaining:  0
> 	- Successful Boot:  1
> 	- Verity Corrupted: 0
>
> Slot[1] Metadata:
> 	- Priority:         14
> 	- Tries Remaining:  7
> 	- Successful Boot:  0
> 	- Verity Corrupted: 0
====

The ab_dump command allows you to display ABC data directly on the
U-Boot console. During an A/B test execution, this test verifies the
accuracy of each field within the ABC data.

Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # vim3_android
Link: https://lore.kernel.org/r/20241017-android_ab_master-v5-5-43bfcc096d95@salutedevices.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>