fix(intel): change SMC return arguments for INTEL_SIP_SMC_MBOX_SEND_CMD

'INTEL_SIP_SMC_MBOX_SEND_CMD' SMC runtime service will only return
mailbox status and the argument's length back to the caller

Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
Change-Id: I50d2ae74845794cab7bf0858e742b5a70e0ea868
1 file changed