imx: support for i.MX8 SoCs misc IPC

NXP's i.MX8 SoCs have system controller (M4 core) which takes
control of misc functions like temperature alarm, dma etc., other
Cortex-A clusters can send out command via MU (Message Unit) to
system controller for misc operation etc..

This patch adds misc IPC(inter-processor communication) support.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
diff --git a/plat/imx/common/include/sci/sci.h b/plat/imx/common/include/sci/sci.h
index 1b2f699..2c45bb8 100644
--- a/plat/imx/common/include/sci/sci.h
+++ b/plat/imx/common/include/sci/sci.h
@@ -16,5 +16,6 @@
 #include <sci/svc/pm/sci_pm_api.h>
 #include <sci/svc/rm/sci_rm_api.h>
 #include <sci/svc/timer/sci_timer_api.h>
+#include <sci/svc/misc/sci_misc_api.h>
 
 #endif /* SCI_H */