On i.MX8QM/i.MX8QX with system controller inside, the SRTC is
managed by SCFW(system controller firmware) and some functions
like setting SRTC's time etc. can ONLY be requested from secure
world, so SIP runtime service is needed for such kind of operations,
this patch adds SRTC SIP runtime service support for i.MX8QM and
i.MX8QX.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>