OpenSBI already implements some extensions that are not ratified yet:

* Debug Console Extension (DBCN)
* System Suspend Extension (SUSP)
* Collaborative Processor Performance Control Extension (CPPC)

Allow the sbi command to display these.

Provide the FID definitions of the Debug Console Extension. We can use that
extension for an early debug console driver.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>