cmd/sbi: display new extensions

The SBI specification v2.0-rc2 defines new extensions:

* Nested Acceleration Extension (NACL)
* Steal Time Accounting (STA)

Allow the sbi command to display these.

Add missing implementation IDs.

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