msm: camera: Adds state variable in mem manager

Add state variable for camera mem manager to show initialization status.
Ensure that all operations are rejected before initialization.

Change-Id: I1ddbaaf6fbed59e4804476562c97f6895d99e916
Signed-off-by: Trishansh Bhardwaj <tbhardwa@codeaurora.org>

drivers/cam_req_mgr/cam_mem_mgr.c

@@ -234,6 +234,11 @@ int cam_mem_get_cpu_buf(int32_t buf_handle, uintptr_t *vaddr_ptr, size_t *len)
 		return -EINVAL;
 	}
 
+	if (!atomic_read(&cam_mem_mgr_state)) {
+		CAM_ERR(CAM_MEM, "failed. mem_mgr not initialized");
+		return -EINVAL;
+	}
+
 	if (!buf_handle || !vaddr_ptr || !len)
 		return -EINVAL;