disp: msm: hdcp: fix compilation of msm_hdcp module on GKI

Add stub functions for msm_hdcp module in order to prevent
linker issues when CONFIG_HDCP_QSEECOM is not defined, marked
as not disabled or defined as module. Furthermore, a Kbuild
entry for the msm_hdcp.h file so that it is exported.

Change-Id: I0f102bf4c9722d95b897facdab94d83e32f7d29f
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>

hdcp/msm_hdcp.c

@@ -53,6 +53,7 @@ void msm_hdcp_register_cb(struct device *dev, void *ctx,
 	hdcp->cb = cb;
 	hdcp->client_ctx = ctx;
 }
+EXPORT_SYMBOL(msm_hdcp_register_cb);
 
 void msm_hdcp_notify_topology(struct device *dev)
 {
@@ -82,6 +83,7 @@ void msm_hdcp_notify_topology(struct device *dev)
 
 	kobject_uevent_env(&hdcp->device->kobj, KOBJ_CHANGE, envp);
 }
+EXPORT_SYMBOL(msm_hdcp_notify_topology);
 
 void msm_hdcp_cache_repeater_topology(struct device *dev,
 			struct HDCP_V2V1_MSG_TOPOLOGY *tp)
@@ -102,6 +104,7 @@ void msm_hdcp_cache_repeater_topology(struct device *dev,
 	memcpy(&hdcp->cached_tp, tp,
 		   sizeof(struct HDCP_V2V1_MSG_TOPOLOGY));
 }
+EXPORT_SYMBOL(msm_hdcp_cache_repeater_topology);
 
 static ssize_t tp_show(struct device *dev, struct device_attribute *attr,
 		char *buf)