Use a command group 'buspirate' with subcommands instead of individual
commands with 'buspirate_' prefix.
The old commands are still available for backward compatibility but
marked as deprecated.
Change-Id: Id999d4ba276af576fb22b76052f3c0a1f3e1b876
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: http://openocd.zylin.com/6404
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>