init shmem early to avoid random crash in fastrpc (#6407)

* init shmem early to avoid possible crash

* fix_code_style

* Keep the initialziation to NULL, remove the duplicate memory allocation

posix-configs/excelsior/mainapp.config

@@ -5,6 +5,7 @@ param set MAV_BROADCAST 1
 param set SDLOG_PRIO_BOOST 3
 dataman start
 navigator start
+sleep 2
 mavlink start -u 14556 -r 1000000
 sleep 1
 mavlink stream -u 14556 -s HIGHRES_IMU -r 50

src/modules/muorb/adsp/px4muorb.cpp

@@ -56,6 +56,7 @@ __END_DECLS
 int px4muorb_orb_initialize()
 {
 	HAP_power_request(100, 100, 1000);
+	shmem_info_p = NULL;
 
 	// The uORB Manager needs to be initialized first up, otherwise the instance is nullptr.
 	uORB::Manager::initialize();

src/modules/uORB/uORBDevices.cpp

@@ -449,7 +449,6 @@ uORB::DeviceNode::publish(const orb_metadata *meta, orb_advert_t handle, const v
 		return ERROR;
 	}
 
-#if !defined(__PX4_QURT_EXCELSIOR) && !defined(__PX4_POSIX_EXCELSIOR)
 	/*
 	 * if the write is successful, send the data over the Multi-ORB link
 	 */
@@ -463,7 +462,6 @@ uORB::DeviceNode::publish(const orb_metadata *meta, orb_advert_t handle, const v
 		}
 	}
 
-#endif
 	return PX4_OK;
 }