feat(intel): support version 2 SiP SVC SMC function ID for mailbox commands

A separated SMC function ID of mailbox command
is introduced for the new format of SMC protocol.

The new format of SMC procotol will be started
using by Zephyr.

Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Signed-off-by: Sieu Mun Tang <sieu.mun.tang@intel.com>
Change-Id: I7996d5054f76c139b5ad55451c373f5669a1017f