fix(drivers/scmi-msg): entry: add weak functions

One platform may not implement all the protocols, to avoid build break
when we not include all the protocols, add weak functions.
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Change-Id: I1485baa2e8f381cb0eede1a7b93ed10e49934971

drivers/scmi-msg/entry.c

@@ -11,6 +11,31 @@
 
 #include "common.h"
 
+#pragma weak scmi_msg_get_clock_handler
+#pragma weak scmi_msg_get_rstd_handler
+#pragma weak scmi_msg_get_pd_handler
+#pragma weak scmi_msg_get_voltage_handler
+
+scmi_msg_handler_t scmi_msg_get_clock_handler(struct scmi_msg *msg __unused)
+{
+	return NULL;
+}
+
+scmi_msg_handler_t scmi_msg_get_rstd_handler(struct scmi_msg *msg __unused)
+{
+	return NULL;
+}
+
+scmi_msg_handler_t scmi_msg_get_pd_handler(struct scmi_msg *msg __unused)
+{
+	return NULL;
+}
+
+scmi_msg_handler_t scmi_msg_get_voltage_handler(struct scmi_msg *msg __unused)
+{
+	return NULL;
+}
+
 void scmi_status_response(struct scmi_msg *msg, int32_t status)
 {
 	assert(msg->out && msg->out_size >= sizeof(int32_t));