plat/synquacer: enable SCMI support

Enable the SCMI protocol support in SynQuacer platform.
Aside from power domain, system power and apcore management protocol,
this commit adds the vendor specific protocol(0x80).
This vendor specific protocol is used to get the dram mapping information
from SCP.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
diff --git a/drivers/arm/css/scmi/scmi_private.h b/drivers/arm/css/scmi/scmi_private.h
index 6530573..61437f6 100644
--- a/drivers/arm/css/scmi/scmi_private.h
+++ b/drivers/arm/css/scmi/scmi_private.h
@@ -152,4 +152,9 @@
 	assert(ch->info && ch->info->scmi_mbx_mem);
 }
 
+/*
+ * SCMI vendor specific protocol
+ */
+#define SCMI_SYS_VENDOR_EXT_PROTO_ID		0x80
+
 #endif /* SCMI_PRIVATE_H */