lib/nhlt: add support for passing subsystem_id to endpoint's structure

This patch adds subsystem_id to nhlt structure whose value is
passed on to the endpoint's structure. Its default value is
retained to be NHLT_SSID.

Change-Id: Iad53f27e958f50e02e928cd8fa60d8397ca0eb06
Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
Reviewed-on: https://review.coreboot.org/26046
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/nhlt.h

@@ -298,6 +298,7 @@ struct nhlt_endpoint {
 
 #define MAX_ENDPOINTS 8
 struct nhlt {
+	uint32_t subsystem_id;
 	uint8_t num_endpoints;
 	struct nhlt_endpoint endpoints[MAX_ENDPOINTS];
 	uint8_t current_instance_id[NHLT_MAX_LINK_TYPES];