treewide: bcb: move ab_select command to bcb subcommands

treewide: bcb: move ab_select command to bcb subcommands

To enhance code organization, it is beneficial to consolidate all A/B
BCB management routines into a single super-command.
The 'bcb' command is an excellent candidate for this purpose.

This patch integrates the separate 'ab_select' command into the 'bcb'
group as the 'ab_select' subcommand, maintaining the same parameter list
for consistency.

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-v5-3-43bfcc096d95@salutedevices.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>